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The systematics of indigenous species of Hieracium Asteraceae in British Columbia Guppy, Geraldine Anne Allen 1975

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THE SYSTEMATICS OF INDIGENOUS SPECIES OF HIERACIUM (ASTERACEAE) IN BRITISH COLUMBIA by GERALDINE ANNE ALLEN GUPPY B . S c , U n i v e r s i t y o f B r i t i s h C o l u m b i a , 1972 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n t h e Department o f Botany We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d The U n i v e r s i t y o f B r i t i s h Columbia September, 1975 In present ing th is thes is in pa r t i a l fu l f i lment of the requirements for an advanced degree at the Un ivers i ty of B r i t i s h Columbia, I agree that the L ibrary shal l make it f ree ly ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th is thes is for s c h o l a r l y purposes may be granted by the Head of my Department or by his representa t ives . It is understood that copying or p u b l i c a t i o n of th is thes is fo r f i n a n c i a l gain sha l l not be allowed without my wr i t ten permiss ion. Department of The Un ivers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 - 11 -ABSTRACT H i e r a c i u m L., a l a r g e and t a x o n o m i c a l l y complex genus i n t h e f a m i l y A s t e r a c e a e , i s r e p r e s e n t e d i n B r i t i s h Columbia by seven s p e c i e s . The p r e s e n t s t u d y was u n d e r t a k e n i n o r d e r t o g a i n i n s i g h t i n t o t h e r e l a t i o n s h i p s between t h e s e s p e c i e s . Data was g a t h e r e d from v a r i o u s s o u r c e s . P a t t e r n s o f m o r p h o l o g i c a l v a r i a t i o n were s t u d i e d , as w e l l as t h e t y p e o f r e p r o d u c t i o n i n each t a x o n and i t s a b i l i t y t o h y b r i d i z e w i t h o t h e r t a x a . Chromosome number, k a r y o t y p e , and m e i o t i c b e h a v i o u r were a l s o i n v e s t i g a t e d . F i v e o f t h e s p e c i e s were examined c h e m i c a l l y and t h e i r f l a v o n o i d s i d e n t i f i e d . The s p e c i e s o f H i e r a c i u m i n B r i t i s h Columbia f a l l i n t o two g r o u p s . The subgenus E u h i e r a c i u m (a p r e d o m i n a n t l y European group) c o n t a i n s one s p e c i e s , H i e r a c i u m umbel!a turn, w hich i s t r i p l o i d , a p o m i c t i c and m o r p h o l o g i c a l l y v a r i a b l e . The o t h e r s i x s p e c i e s b e l o n g t o the subgenus S t e n o t h e c a (a m a i n l y New World g r o u p ) . W i t h i n the subgenus t h e y form t h r e e c l u s t e r s o f one o r more s p e c i e s each, a l l o f w hich a r e d i p l o i d and s e x u a l l y r e p r o d u c i n g . The c l u s t e r s a r e m o r p h o l o g i c a l l y and c h e m i c a l l y d i s t i n c t f r o m one a n o t h e r , and d i f f e r i n r e p r o d u c t i v e s t r a t e g y . However, t h e y have v e r y s i m i l a r chromosomes and a r e i n t e r f e r t i l e . The h y b r i d s between s p e c i e s o f d i f f e r e n t c l u s t e r s , though t h e y have l o w e r e d p o l l e n v i a b i l i t y , a r e a l l m e i o t i c a l l y r e g u l a r ( i n d i c a t i n g c l o s e r e l a t i o n s h i p s between the p a r e n t s ) . W i t h i n t h e c l u s t e r s t h e s p e c i e s i n t e r g r a d e m o r p h o l o g i c a l l y and r e p r o d u c t i v e l y , and a r e c h e m i c a l l y s i m i l a r ( w i t h t h e e x c e p t i o n o f H i e r a c i u m t r i s t e and H_. g r a c i l e , w h i c h d i f f e r c h e m i c a l l y ) . A s y n o p s i s o f t h e seven H i e r a c i u m s p e c i e s i s - i i i -TABLE OF CONTENTS page ABSTRACT i i ACKNOWLEDGEMENTS x I. INTRODUCTION 1 I I . MORPHOLOGY 5 S p e c i e s o f t h e Subgenus E u h i e r a c i u m 6 The H i e r a c i u m s c o u l e r i Complex and H i e r a c i u m a l b i f l o r u m . 24 (1) V a r i a t i o n w i t h i n t h e H i e r a c i u m s c o u l e r i complex . 26 (2) V a r i a t i o n i n H i e r a c i u m a l b i f l o r u m 30 (3) The r e l a t i o n s h i p between t h e H i e r a c i u m s c o u l e r i complex and H i e r a c i u m a l b i f l o r u m . . . 32 The H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e Complex . . . . 39 I I I . REPRODUCTIVE BIOLOGY 47 B r e e d i n g System 48 H y b r i d i z a t i o n E x p e r i m e n t s 56 P o l l e n V i a b i l i t y 66 IV. CYTOGENETICS 69 Methods 69 R e s u l t s 76 (1) Chromosome number 76 (2) K a r y o t y p e 77 (3) M e i o s i s 83 - i v -page V. FLAVONOID CHEMISTRY 92 Methods 93 R e s u l t s 98 VI . DISCUSSION 122 T h e o r e t i c a l C o n s i d e r a t i o n s 122 The S p e c i e s o f H i e r a c i u m : B i o l o g y and I n t e r r e l a t i o n s h i p s . 123 (1) The North American H i e r a c i u m umbel!atum complex . 123 (2) The H i e r a c i u m s c o u l e r i complex 128 (3) H i e r a c i u m a l b i f l o r u m 133 (4) The H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e complex . 136 (5) R e l a t i o n s h i p s between s e c t i o n s 142 (6) The p o s i t i o n o f t h e genus w i t h i n t h e C i c h o r i e a e . 143 A S y n o p s i s o f H i e r a c i u m S p e c i e s i n B r i t i s h C o l umbia . ... 146 LITERATURE CITED 148 - V -LIST OF TABLES page I. M o r p h o l o g i c a l f e a t u r e s o f some North A merican s p e c i e s o f H i e r a c i u m subgenus E u h i e r a c i u m , based on p u b l i s h e d d e s c r i p t i o n s 8 I I . C o l l e c t i o n s i t e s o f t h e p l a n t m a t e r i a l used f o r b r e e d i n g e x p e r i m e n t s 49 I I I . R e s u l t s o f e x p e r i m e n t s t o d e t e r m i n e b r e e d i n g system . . 54 IV. S t a t i s t i c a l c o m p a r i s o n s o f g e r m i n a t i o n r a t e s 55 V. M o r p h o l o g i c a l f e a t u r e s o f t h e h y b r i d s o b t a i n e d from c r o s s i n g e x p e r i m e n t s 60 VI. P o l l e n v i a b i l i t y 67 V I I . C o l l e c t i o n s i t e s o f p l a n t m a t e r i a l used f o r chromosome s t u d i e s 71 V I I I . S o u r c e s o f p l a n t m a t e r i a l used f o r c h e m i c a l a n a l y s e s . . 94 IX. Rf v a l u e s and c o l o u r r e a c t i o n s o f H i e r a c i u m f l a v o n o i d s . . 99 X. D i s t r i b u t i o n o f t h e f l a v o n o i d compounds i n s p e c i e s o f H i e r a c i u m 103 - v i -LIST OF FIGURES page 1. S p e c i e s o f H i e r a c i u m found i n B r i t i s h C o l u m b i a , a c c o r d i n g t o C r o n q u i s t (1955a) 3 2. The H i e r a c i u m umbel l a t u m complex: c o l l e c t i o n s i t e s o f a l l m a t e r i a l examined from w e s t e r n N o r t h America 15 3. The H i e r a c i u m umbellatum complex: c o l l e c t i o n s i t e s o f a l l m a t e r i a l examined from o t h e r r e g i o n s 16 4. L e a f l e n g t h - t o - w i d t h r a t i o s i n t h e H i e r a c i u m umbellatum complex i n w e s t e r n N o r t h America 17 5. L e a f l e n g t h - t o - w i d t h r a t i o s i n t h e H i e r a c i u m umbellatum complex i n E u r o p e , A s i a and e a s t e r n N o r t h America 18 6. M o r p h o l o g i c a l v a r i a t i o n i n t h e H i e r a c i u m umbellatum complex i n w e s t e r n N o r t h America 20 7. M o r p h o l o g i c a l v a r i a t i o n i n t h e H i e r a c i u m umbellatum complex i n e a s t e r n N o r t h A m e r i c a , Europe and A s i a 21 8. Numbers o f f l o w e r heads i n t h e H i e r a c i u m umbellatum complex . 25 9. C o l l e c t i o n s i t e s o f a l l m a t e r i a l examined o f t h e H i e r a c i u m s c o u l e r i complex 27 10. M o r p h o l o g i c a l v a r i a t i o n i n t h e H i e r a c i u m s c o u l e r i complex . . 29 11. Numbers o f f l o w e r heads i n t h e s p e c i e s o f t h e Hlteracium s c o u l e r i complex. . 31 12. C o l l e c t i o n s i t e s o f a l l m a t e r i a l examined o f H i e r a c i u m a l b i f l o r u m 33 13. M o r p h o l o g i c a l v a r i a t i o n i n H i e r a c i u m a l b i f l o r u m 34 14. V a r i a t i o n i n numbers o f f l o w e r heads i n H i e r a c i u m a l b i f l o r u m . 35 15. R e l a t i v e abundance o f s t e l l a t e h a i r s i n H i e r a c i u m a l b i f l o r u m and i n t h e H i e r a c i u m s c o u l e r i complex 37 16. C o l l e c t i o n s i t e s o f a l l m a t e r i a l examined o f H i e r a c i u m t r i s t e and H i e r a c i u m g r a c i l e 40 - v i i -page 17. M o r p h o l o g i c a l v a r i a t i o n i n the H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e complex 42 18. Numbers o f f l o w e r heads i n the H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e complex 45 19. I n f r a r e d s p e c t r a o f a p i g e n i n 7 - 0 - B - D - g l u c u r o n i d e and i t s y - l a c t o n e 101 20. The p r o b a b l e b i o s y n t h e s i s o f t h e f l a v o n o i d a g l y c o n e s f o u n d i n H i e r a c i u m 107 21. P o s s i b l e g l y c o s y l a t i n g enzymes i n t h e d i f f e r e n t s p e c i e s o f H i e r a c i u m 109 22. H y p o t h e t i c a l r e l a t i o n s h i p s among t h e western N o r t h American s p e c i e s o f H i e r a c i u m subgenus S t e n o t h e c a 144 - v i i i -LIST OF PLATES page 1. H i e r a c i u m g r a c i l e on a m o u n t a i n s i d e southwest o f H e d l e y , B r i t i s h Columbia x i i 2. P r e s s e d specimens o f H i e r a c i u m c y n o g l o s s o i d e s , H. g r a c i l e , and t h e - a r t i f i c i a l l y p roduced f i r s t - g e n e r a t i o n h y b r i d between them 62 3. Flower heads o f H i e r a c i u m s c o u l e r i , H_. a l b i f l o r u m and a n a t u r a l h y b r i d between them 64 4. A n a t u r a l h y b r i d between H i e r a c i u m a l b i f l o r u m and H_. g r a c i l e . 65 5. K a r y o t y p e o f H i e r a c i u m umbellatum . . . . 78 6. K a r y o t y p e o f H i e r a c i u m umbellatum 78 7. K a r y o t y p e o f H i e r a c i u m a l b e r t i n u m 79 8. K a r y o t y p e o f H i e r a c i u m c y n o g l o s s o i d e s 79 9. K a r y o t y p e o f H i e r a c i u m s c o u l e r i 80 10. K a r y o t y p e o f H i e r a c i u m a l b i f l o r u m 80 11. K a r y o t y p e o f H i e r a c i u m t r i s t e 81 12. K a r y o t y p e o f H i e r a c i u m g r a c i l e 81 13. M e i o s i s ( d i a k i n e s i s ) i n p o l l e n mother c e l l s o f H i e r a c i u m  umbellatum 85 14. Metaphase I i n H i e r a c i u m umbellatum 85 15. Metaphase I i n H i e r a c i u m umbellatum 85 16. Anaphase I i n H i e r a c i u m umbellatum 85 17. D i a k i n e s i s i n H i e r a c i u m a l b e r t i n u m 87 18. Metaphase I i n H i e r a c i u m a l b e r t i n u m 87 19. D i a k i n e s i s i n H i e r a c i u m c y n o g l o s s o i d e s 87 20. Metaphase I i n H i e r a c i u m c y n o g l o s s o i d e s 87 21. D i a k i n e s i s i n H i e r a c i u m s c o u l e r i 88 - i x -page 22. Metaphase I i n H i e r a c i u m s c o u l e r i 88 23. D i a k i n e s i s i n H i e r a c i u m a l b i f l o r u m . . . . . 88 24. Metaphase I i n H i e r a c i u m a l b i f l o r u m 88 25. Metaphase I i n H i e r a c i u m g r a c i l e 89 26. Anaphase I i n H i e r a c i u m g r a c i l e 89 27. D i a k i n e s i s i n H i e r a c i u m g r a c i l e 89 28. Metaphase I i n H i e r a c i u m g r a c i l e 89 29. D i a k i n e s i s i n p o l l e n mother c e l l s o f H i e r a c i u m a l b i f l o r u m X H. a l b e r t i n u m 91 30. Metaphase I i n H i e r a c i u m a l b i f l o r u m X H_. a l b e r t i n u m . . . . 91 31. Metaphase I i n H i e r a c i u m g r a c i l e X H_. s c o u l e r i 91 32. Metaphase I i n H i e r a c i u m g r a c i l e X H_. a l b i f l o r u m 91 33. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m umbellatum . . . 113 34. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m a l b e r t i n u m . . . 113 35. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m c y n o g l o s s o i d e s . . 114 36. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m s c o u l e r i . . . . 114 37. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m a l b i f l o r u m . . . 115 38. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m t r i s t e . . . . 115 39. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m g r a c i l e . . . . 116 40. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m g r a c i l e X H. a l b i f l o r u m 116 41. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m g r a c i l e X H_. c y n o g l o s s o i d e s 117 42. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m a l b i f l o r u m X H. s c o u l e r i 117 - x -ACKNOWLEDGEMENTS I would l i k e t o e x p r e s s my a p p r e c i a t i o n t o my g r a d u a t e a d v i s e r , Dr. Roy L. T a y l o r o f the U n i v e r s i t y o f B r i t i s h Columbia B o t a n i c a l Garden, f o r h i s h e l p and gu i d a n c e t h r o u g h o u t t h e c o u r s e o f t h i s r e s e a r c h and d u r i n g the p r e p a r a t i o n o f the t h e s i s . Dr. Bruce A. Bohm o f the Department o f Botany, U n i v e r s i t y o f B r i t i s h C olumbia, p r o v i d e d me w i t h l a b o r a t o r y space f o r the c h e m i c a l r e s e a r c h , and was generous w i t h a s s i s t a n c e and a d v i c e r e g a r d i n g t h i s p o r t i o n o f t h e work. Dr. F. W i l l i a m C o l l i n s (now o f t h e Department o f Botany, U n i v e r s i t y o f T o r o n t o ) p r o v i d e d much u s e f u l a d v i c e and d i s c u s s i o n c o n c e r n i n g c h e m i c a l t e c h n i q u e s . Dr. C h r i s t o p h e r J . Marchant ( R e s e a r c h S c i e n t i s t , U n i v e r s i t y o f B r i t i s h Columbia B o t a n i c a l Garden) a s s i s t e d me w i t h t e c h n i q u e s f o r the h a n d l i n g o f chromosomes. I would l i k e t o thank Dr. J i m P o j a r and Dr. Nancy T u r n e r , both o f whom h e l p e d me by c o l l e c t i n g p l a n t m a t e r i a l , and Dr. Rob e r t J . Bose ( F i s h e r i e s Research L a b o r a t o r y , Environment Canada) who d i d the NMR s p e c t r a . My husband, A r t h u r Guppy, accompanied me on most o f the f i e l d e x p e d i t i o n s and a l s o c o l l e c t e d c o n s i d e r a b l e p l a n t m a t e r i a l d u r i n g h i s own t r a v e l s . He has p r o v i d e d c o n s i d e r a b l e moral s u p p o r t t h r o u g h o u t t h e c o u r s e o f t h i s work. T h i s work was g r e a t l y f a c i l i t a t e d by t h e r e c e i p t o f s c h o l a r s h i p s from the N a t i o n a l Research C o u n c i l o f Canada (1972-1974). The l a b o r a t o r y and - x i -f i e l d r e s e a r c h was f i n a n c e d by N a t i o n a l Research C o u n c i l o f Canada G r a n t 67-5705 t o Dr. T a y l o r . - x i i -P l a t e 1. H i e r a c i u m g r a c i l e ( s l e n d e r hawkweed) on a m o u n t a i n s i d e southwest o f H e d l e y , B r i t i s h Columbia. - 1 -I. INTRODUCTION The hawkweed genus, H i e r a c i u m L., i s a v e r y l a r g e and complex genus i n the t r i b e C i c h o r i e a e o f the f a m i l y A s t e r a c e a e . I t i s w i d e l y d i s t r i b u t e d , o c c u r r i n g on e v e r y c o n t i n e n t e x c e p t A u s t r a l i a . The c o m p l e x i t y o f t h e group i s r e f l e c t e d i n t h e l i t e r a t u r e . A lmost 10,000 s p e c i e s have a t one time o r a n o t h e r been d e s c r i b e d ( C r o n q u i s t 1955a), though i t i s p r o b a b l e t h a t t h e s e c o u l d r e a s o n a b l y be r e d u c e d t o a few hundred. In t h e d i s c u s s i o n o f t h e C i c h o r i e a e by S t e b b i n s (1953) H i e r a c i u m i s i n c l u d e d i n the s u b t r i b e C r e p i d i n a e , where i t l i e s on one o f s e v e r a l e v o l u t i o n a r y l i n e s r a d i a t i n g o u t from t h e p r i m i t i v e genus Dubyaea. Oth e r well-known members o f t h i s s u b t r i b e a r e Taraxacum, L a c t u c a and C r e p i s . The n e a r e s t r e l a t i v e o f H i e r a c i u m i s t h e s m a l l M e d i t e r r a n e a n genus A n d r y a l a . H i e r a c i u m p r e s e n t s an a s s o r t m e n t o f d i f f i c u l t and i n t e r e s t i n g taxonomic problems. A f r e q u e n t l y e n c o u n t e r e d c o m b i n a t i o n o f a p o m i x i s (which i s wi d e s p r e a d w i t h i n t he genus) and o c c a s i o n a l s e x u a l r e p r o d u c t i o n has r e s u l t e d i n p a t t e r n s o f v a r i a b i l i t y which can be f i t t e d o n l y w i t h d i f f i c u l t y i n t o the c o n v e n t i o n a l taxonomic h i e r a r c h y . A c c o r d i n g l y , t he l i t e r a t u r e c o n t a i n s many d i f f e r i n g o p i n i o n s . The most comprehensive t r e a t m e n t o f H i e r a c i u m t o date i s t h e w o r l d monograph by Zahn, which appeared i n E n g l e r ' s Das P f l a n z e n r e i c h between 1921 and 1923. Zahn d e s c r i b e d 756 s p e c i e s (and numerous t a x a below t h e s p e c i e s l e v e l ) which he grouped i n t o f o u r s u b g e n e r a , as f o l l o w s : (1) E u h i e r a c i u m - t h e l a r g e s t group, f o u n d m o s t l y i n the O l d World; p l a n t s g e n e r a l l y l a r g e and s t u r d y . C o n t a i n s many a p o m i c t i c t a x a . (2) S t e n o t h e c a - p r e d o m i n a n t l y o f t h e New World. No a p o m i c t i c t a x a - 2 -a r e known. (3) Mandonia - a s m a l l group, found o n l y a t h i g h e l e v a t i o n s i n the mountains o f South America. No d a t a i s a v a i l a b l e c o n c e r n i n g t h e o c c u r r e n c e o f a p o m i x i s . (4) Pi l o s e ! l a - p l a n t s s t o l o n i f e r o u s and p r o s t r a t e ; c o n f i n e d t o the Old World. C o n t a i n s numerous a p o m i c t i c t a x a . A l l the North American s p e c i e s b e l o n g t o the f i r s t two o f t h e s e f o u r g r o u p s . T h e r e a r e perhaps e i g h t s p e c i e s o f H i e r a c i u m i n d i g e n o u s t o B r i t i s h Columbia, the number v a r y i n g a c c o r d i n g t o the a u t h o r c o n s u l t e d . P u b l i c a t i o n s t h a t c o n s i d e r B r i t i s h Columbian hawkweed s p e c i e s i n c l u d e those o f P o r s i l d ( 1 9 5 1 ) , C r o n q u i s t ( 1 9 5 5 a ) , Lepage (1958, 1960, 1961), C a l d e r & T a y l o r ( 1 9 6 8 ) , and H u l t e n (1968). I t was c o n v e n i e n t t o t a k e one o f t h e s e as a s t a r t i n g p o i n t , and t h e r e f o r e t h e s p e c i e s u n i t s used f o r much o f t h i s s t u d y a r e t h o s e o f C r o n q u i s t (1955a). They a r e g i v e n i n F i g u r e 1, f i t t e d i n t o the framework o f t h e c l a s s i f i c a t i o n scheme o f Zahn. On the b a s i s o f a c a s u a l i n s p e c t i o n t h e s e s p e c i e s f a l l i n t o t h r e e r e a d i l y d e f i n a b l e g r o u p s , which c o r r e s p o n d w e l l w i t h Zahn's i n f r a g e n e r i c c a t e g o r i e s . P l a n t s o f t h e subgenus E u h i e r a c i u m , which form the f i r s t gro.up, a r e t a l l and r o b u s t h e r b s o f low t o m i d d l e e l e v a t i o n s i n B r i t i s h C olumbia. The second group i n c l u d e s p l a n t s o f medium s i z e , a l s o o f m i d d l e e l e v a t i o n s , and commonly w i t h l o n g s e t o s e h a i r s on the l e a v e s ( s p e c i e s o f s e c t i o n s T h y r s o i d e a and P u l m o n a r e i f o r m i a ) . The t h i r d group c o n s i s t s o f s m a l l p l a n t s o f a l p i n e o r a r c t i c h a b i t a t s ( s p e c i e s o f s e c t i o n A u r e l l i f o r m i a ) . Most d i s a g r e e m e n t on the taxonomy o f t h e hawkweeds o f - 3 -F i g u r e 1. S p e c i e s o f H i e r a c i u m f o u n d i n B r i t i s h Columbia, a c c o r d i n g t o C r o n q u i s t (1955a). ( S u p r a s p e c i f i c g r o u p i n g s t a k e n from Zahn, 1921-1923) Subgenus E u h i e r a c i u m S e c t i o n 16. T r i d e n t a t a . H i e r a c i u m canadense Michx. S e c t i o n 17. Umbel!a,ta. H_. umbel!atum L. Subgenus S t e n o t h e c a S e c t i o n 35. P u l m o n a r e i f o r m i a . H_. a l b i f l o r u m Hook. S e c t i o n 37. T h y r s o i d e a . H. s c o u l e r i Hook. H_. c y n o g l o s s o i d e s Arv.-Touv. H_. a l b e r t i n u m F a r r S e c t i o n 38. A u r e l 1 i f o r m i a . H. t r i s t e W i l I d . H_. g r a c i l e Hook. Note: Each o f the above s e c t i o n s c o n t a i n s o t h e r s p e c i e s n o t f o u n d i n B r i t i s h Columbia. V a r i o u s i n f r a s p e c i f i c t a x a , not i n c l u d e d h e r e , have a l s o been p r o p o s e d . - 4 -B r i t i s h Columbia a r i s e s from t h e f a c t t h a t t h e y i n t e r g r a d e f r e e l y w i t h i n each o f t h e s e t h r e e g r o u p s . The r e s u l t i n g v a r i a b i l i t y may o r may n o t be c o r r e l a t e d w i t h g e o g r a p h i c d i s t r i b u t i o n . T h e r e i s a l s o d i s a g r e e m e n t r e g a r d i n g t he s t a t u s o f t h e s e s p e c i e s w i t h r e s p e c t t o r e l a t e d t a x a o c c u r r i n g e l s e w h e r e . The purpose o f t h i s s t u d y i s t o c r i t i c a l l y examine the s p e c i e s o f H i e r a c i u m growing n a t u r a l l y i n B r i t i s h C o lumbia, t o g a t h e r p r e v i o u s l y u n a v a i l a b l e i n f o r m a t i o n on the b i o l o g y o f t h e s e p l a n t s , and t o a s s e s s by v a r i o u s means t h e r e l a t i o n s h i p s w i t h i n and between groups . A number o f d i f f e r e n t a p p r o a c h e s have been employed. These i n c l u d e c y t o g e n e t i c s t u d i e s and k a r y o t y p e a n a l y s i s , a s sessment o f m o r p h o l o g i c a l v a r i a t i o n , f i e l d s t u d i e s on b r e e d i n g system and c r o s s a b i l i t y , and c o m p a r a t i v e a n a l y s i s o f f l a v o n o i d c h e m i s t r y . The p r e s e n t d i v i s i o n s between t a x a a r e i n many ways u n s a t i s f a c t o r y , and i t i s hoped t h a t t h e i n f o r m a t i o n p r e s e n t e d here w i l l c o n t r i b u t e t o a taxonomic t r e a t m e n t t h a t more a c c u r a t e l y r e f l e c t s e x i s t i n g r e l a t i o n s h i p s . - 5 -I I . MORPHOLOGY Most s y s t e m a t i c t r e a t m e n t s o f p l a n t groups a r e based on morphology. M o r p h o l o g i c a l d i f f e r e n c e s o f f e r a c o n v e n i e n t and o b v i o u s b a s i s f o r the s e p a r a t i o n o f s p e c i e s , and were used by e a r l y b o t a n i s t s l o n g b e f o r e the time o f L i n n a e u s . T h i s s t u d y attempts t o a s s e s s t h e v a r i a b i l i t y o f m o r p h o l o g i c a l c h a r a c t e r s which have been used t o c l a s s i f y the H i e r a c i u m s p e c i e s f o u n d i n B r i t i s h Columbia, t o show how t h e s e c h a r a c t e r s c o r r e l a t e w i t h one a n o t h e r , and t o e s t i m a t e t h e i r taxonomic v a l u e . I have assumed the c h a r a c t e r s o f g r e a t e s t taxonomic importance t o be t h o s e t h a t c o r r e l a t e w i t h the l a r g e s t number o f o t h e r c h a r a c t e r s . Both f i e l d m a t e r i a l and h e r b a r i u m specimens were used f o r m o r p h o l o g i c a l s t u d y . M a t e r i a l from the f o l l o w i n g h e r b a r i a was examined: U n i v e r s i t y o f A l a s k a (ALA) -- H i e r a c i u m t r i s t e and H_. g r a c i l e Dudley Herbarium, S t a n f o r d U n i v e r s i t y (DS) -- H_. t r i s t e and H_. g r a c i l e ; H^ . umbellatum Department o f A g r i c u l t u r e , Ottawa (DAO) -- H_. t r i s t e and jH. g r a c i l e ; H_. umbellatum and r e l a t e d s p e c i e s N a t i o n a l Museum o f Canada, Ottawa (CAN) -- H_. t r i s t e and H_. g r a c i l e ; H_. umbellatum and r e l a t e d s p e c i e s B r i t i s h Columbia P r o v i n c i a l Museum, V i c t o r i a (V) -- a l l i n d i g e n o u s t a x a U n i v e r s i t y o f B r i t i s h Columbia (UBC) -- a l l i n d i g e n o u s t a x a For m o r p h o l o g i c a l comparisons the p l a n t specimens were s e p a r a t e d i n t o t h r e e g r o u p s : (a) the H_. umbellatum complex (subgenus E u h i e r a c i u m ) , (b) t h e H_. s c o u l e r i complex and H_. a l b i f l o r u m , and ( c ) the H_. t r i s t e -- 6 -H_. g r a c i l e complex. The groups a r e d i s c u s s e d s e p a r a t e l y , s i n c e t h e y a r e m o r p h o l o g i c a l l y d i s t i n c t and t h e v a r i a t i o n w i t h i n each group i s o f p a r t i c u l a r i n t e r e s t . Any c h a r a c t e r s t h a t were c o n s p i c u o u s l y v a r i a b l e were examined, i n a d d i t i o n t o t h o s e used by p r e v i o u s workers i n the c l a s s i f i c a t i o n o f the group. Fo r each group an e f f o r t was made to o b t a i n m a t e r i a l from a l l p a r t s o f t h e range. T h i s was most d i f f i c u l t w i t h s p e c i e s o c c u r r i n g i n E u r o p e , but even t h o s e s p e c i e s found o n l y i n North America are more s p a r s e l y r e p r e s e n t e d from the American p a r t s o f t h e i r range. The c o l l e c t i o n s i t e s o f a l l the specimens examined a r e mapped i n F i g u r e s 2, 3, 9, 12 and 16. S p e c i e s o f t h e Subgenus E u h i e r a c i u m . T h i s i s a w i d e s p r e a d and d i f f i c u l t group o f s p e c i e s which has been the s u b j e c t o f c o n s i d e r a b l e d i s a g r e e m e n t . O n l y Zahn, i n h i s monograph (1921-1923), has attempted t o produce a u n i f o r m taxonomic t r e a t m e n t o f a l l the s p e c i e s , though o t h e r a u t h o r s have p u b l i s h e d d e s c r i p t i o n s based on t h e s t u d y o f r e g i o n a l f l o r a s . In N o r t h America t h e r e a r e two, o r perhaps t h r e e s p e c i e s o f H i e r a c i u m r e l a t e d t o H_. umbellatum L. The e x a c t r e l a t i o n s h i p between t h e s e s p e c i e s , and the European H_. umbellatum f i r s t d e s c r i b e d by L i n n a e u s , i s not c l e a r . The V a r i a b i l i t y o f the O l d World s p e c i e s (many o f which a r e a p o m i c t i c ) has made a u n i v e r s a l l y a c c e p t a b l e c l a s s i f i c a t i o n o f European hawkweeds d i f f i c u l t t o a c h i e v e . As a r e s u l t , t h e name H_. umbel l a t u m i n Europe d e s c r i b e s d i f f e r e n t e n t i t i e s from one a u t h o r t o the n e x t . - 7 -The N o r t h American p l a n t s appear t o form a continuum between two m o r p h o l o g i c a l t y p e s . One o f t h e s e has narrow ( u s u a l l y l a n c e o l a t e ) l e a v e s w i t h s h o r t , s t i f f , c l o s e l y spaced s u b c o n i c h a i r s on the m a r g i n s . T h i s has been r e g a r d e d by some a u t h o r s (Gray 1888, F e r n a l d 1950, C r o n q u i s t 1955a, G l e a s o n 1963) as a p a r t o f H. umbel!atum L.; by o t h e r s (Rydberg 1922, Lepage 1960 and 1971, H u l t d n 1968) i t has been c o n s i d e r e d a s e p a r a t e and s t r i c t l y N o rth American s p e c i e s , H_. s c a b r i u s c u l u m Schwein. The o t h e r m o r p h o l o g i c a l extreme has w i d e r ( u s u a l l y l a n c e o l a t e - o v a t e ) l e a v e s l a c k i n g s u b c o n i c h a i r s and o f t e n c l a s p i n g t h e stem. T h i s i s u s u a l l y c a l l e d H_. canadense Michx. Lepage (1960) s e p a r a t e d a p o r t i o n o f t h i s t a x on as H_. k a l m i i L., a s i m i l a r s p e c i e s w i t h n a r r o w e r and more a c u t e i n v o l u c r a l b r a c t s . A l l t h r e e o f t h e s p e c i e s , as d e f i n e d h e r e , a r e e x t r e m e l y v a r i a b l e , and many a u t h o r s have e s t a b l i s h e d i n f r a s p e c i f i c s e g r e g a t e s . Lepage, f o r example .(I960, 1961) d e s c r i b e s a t o t a l o f t w e l v e v a r i e t i e s . Because t h e v a r i a t i o n i s more o r l e s s c o n t i n u o u s , most d i s a g r e e m e n t i s c o n c e r n e d w i t h t h e d e l i m i t a t i o n o f s p e c i e s . O p i n i o n a l s o d i f f e r s o v e r which c h a r a c t e r s have t h e g r e a t e s t d i a g n o s t i c v a l u e , and which taxonomic l e v e l s a r e most a p p r o p r i a t e . T a b l e I l i s t s t h e main d e s c r i p t i o n s o f North American m a t e r i a l t h a t have appeared i n p r i n t (as w e l l as two d e s c r i p t i o n s f r o m p r e d o m i n a n t l y European t r e a t m e n t s ) , t o g e t h e r w i t h a u t h o r s and d a t e s f o r each. Only t h e c h a r a c t e r s c o n s i d e r e d by each a u t h o r t o be u s e f u l i n s e p a r a t i n g the s p e c i e s a r e i n c l u d e d i n the t a b l e . About 300 specimens were examined i n the p r e s e n t s t u d y . Most o f t h e s e a r e f r o m B r i t i s h Columbia o r a d j a c e n t r e g i o n s , but some m a t e r i a l f r o m T a b l e I. M o r p h o l o g i c a l f e a t u r e s o f some N o r t h American s p e c i e s o f H i e r a c i u m subgenus E u h i e r a c i u m , based on p u b l i s h e d d e s c r i p t i o n s . L e a f s i z e A u t h o r and Date L e a f margin and shape Stem I n f l o r e s c e n c e I n v o l u c r e R e c e p t a c l e H. umbellatum L. Gray 1888 l e a v e s n a r r o w l y ( o c c a s i o n -a l l y b r o a d -l y ) l a n c e o -l a t e , n e v e r c l a s p i n g s u b u m b e l l a t e , f l o w e r heads few g l a b r o u s o r n e a r l y s o , b r a c t s s p r e a d i n g Henry 1915 l e a v e s n a r r o w l y l a n c e o l a t e 3 t o 5 dm h i g h f l o w e r heads few Zahn 1922 l e a v e s l i n e a r t o l a n c e o l a t e o r o b l a n -c e o l a t e umbel l a t e , p a n i c u l a t e below b r a c t s a c u t e , s p r e a d i n g Farwel1 1927 l e a v e s s m a l l e r upward no l o n g h a i r s a t base g l a b r o u s P u g s l e y 1948 s c a b r o u s ( i . e . w i t h s u b c o n i c h a i r s ) ; sub-e n t i r e t o d e n t i c u l a t e l e a v e s l i n e a r t o n a r r o w l y l a n c e o l a t e ; o f t . crowded su b u m b e l l a t e g l a b r o u s o r s l i g h t l y g l a n d u l a r o r s t e l l a t e 00 I w i t h i r r e g -u l a r l y d e n t a t e o r d e n t a t e - f i m b r i a t e p i t s T a b l e I. ( c o n t ' d ) L e a f s i z e A u t h o r and Date L e a f margin and shape Stem I n f l o r e s c e n c e I n v o l u c r e R e c e p t a c l e F e r n a l d 1950 s c a b r o u s C r o n q u i s t 1955a G l e a s o n 1963 Welsh 1974 w i t h s u b c o n i c h a i r s w i t h s u b c o n i c h a i r s w i t h s u b c o n i c h a i r s s c a b r i u s c u l u m Schwein. S c h w e i n i t z 1824 s c a b r o u s l e a v e s l i n e a r t o l a n c e o l a t e , n o t c l a s p i n g l e a v e s 4 t o 12 t i m e s as l o n g as wide, not c l a s p i n g l e a v e s 4 t o 12 t i m e s as l o n g as w i de, not c l a s p i n g l e a v e s l a n c e - o b l o n g , sometimes somewhat c l a s p i n g 1 eaves wide and c l a s p i n g , s m a l l e r upwards no l o n g h a i r s a t base no l o n g h a i r s a t base a sub-u m b e l l a t e p a n i c l e g l a n d l e s s p i t s w i t h f i m b r i a t e edges g l a b r o u s o r n e a r l y so g l a b r o u s n e a r l y g l a b r o u s T a b l e I. ( c o n t ' d ) A u t h o r and Date Rydberg 1922 L e a f m a r g i n L e a f s i z e and shape Stem I n f l o r e s c e n c e I n v o l u c r e R e c e p t a c l e Lepage Hulte'n 1960 1968 s c a b r o u s -p u b e r u l e n t s c a b r o u s ; d e n t a t e t o e n t i r e w i t h s u b c o n i c hai r s ; r e m o t e l y t o o t h e d l e a v e s l a n c e o l a t e t o ob-l a n c e o l a t e l e a v e s not c l a s p i n g l e a v e s o v a t e -l a n c e o l a t e , c l a s p i n g JH. umbellatum L. v a r . s c a b r i u s c u l u r n (Schwein.) Farw. F a r w e l l 1927 l e a v e s not s m a l l e r upwards H_. canadense Michx. Michaux 1803 d e n t a t e l e a v e s l a n c e o l a t e , somewhat c l a s p i n g no l o n g h a i r s a t base g l a b -rous l o n g h a i r s a t base corymbose p a n i c u l a t e a corymb, f l o w e r heads few g l a b r o u s o r n e a r l y so b r a c t s 15 t o 25 mm l o n g tomentose [ s t e l l a t e ] p u b e s c ent m i n u t e l y h i s p i d o i T a b l e I. ( c o n t ' d ) A u t h o r and Date and Gray Gray Henry L e a f m a r g i n L e a f s i z e and shape Stem I n f l o r e s c e n c e I n v o l u c r e R e c e p t a c l e 1843 s c a b r o u s - l e a v e s c i l i o l a t e narrow t o w i d e , sometimes c l a s p i n g 1888 l e a v e s l a n c e o l a t e t o o v a t e , c l a s p i n g o r broad a t base 1915 l e a v e s 5 t o b r o a d l y 9 dm l a n c e o l a t e h i g h 1950 s l i g h t l y l e a v e s l o n g t o not a t a l l l a n c e o l a t e h a i r s s c a b r o u s t o n a r r o w l y a t o v a t e , base rounded t o c l a s p i n g 1955a s u b c o n i c l e a v e s l o n g h a i r s a b s e n t 2 t o 5 times h a i r s o r few and as l o n g as a t p o o r l y wide, some- base d e v e l o p e d t i m e s somewhat c l a s p i n g a corymb o r p a n i c u l a t e cyme, f l o w e r heads many f l o w e r heads many a p a n i c l e o r p a n i c u l a t e corymb somewhat g l a b r o u s g l a b r a t e t o g l a n d u l a r , b r a c t s a p p r e s s e d w i t h a few g l a n d s ( a t l e a s t when young) p i t s w i t h s h a l l o w l y d e n t a t e margins T a b l e I. ( c o n t ' d ) A u t h o r and Date L e a f m a r g i n L e a f s i z e and shape Stem I n f l o r e s c e n c e I n v o l u c r e R e c e p t a c l e Lepage 1960 d e n t a t e , n o t s c a b r o u s G l e a s o n 1963 no s u b c o n i c h a i r s H_. umbellatum L. v a r . canadense (Michx.) B r e i t u n g Brei.tung 1957 H_. columbianum Rydb. Rydberg 1901 l e a v e s ob-l a n c e o l a t e o r l a n c e o -l a t e t o o v a t e -l a n c e o l a t e base upper l e a v e s l o n g t r i a n g u l a r , h a i r s t r u n c a t e t o a t c o r d a t e a t base l e a v e s 2 t o 5 t i m e s as l o n g as wide, somewhat c l a s p i n g w i t h l o n g s p r e a d i n g h a i r s l o n g h a i r s a t base a corymbose cyme, f l o w e r heads few b r a c t s 10 t o 15 mm l o n g , o b l o n g -l a n c e o l a t e I p u b e r u l e n t when young, g l a b r o u s i n age T a b l e I. ( c o n t ' d ) A u t h o r and Date L e a f margin L e a f s i z e and shape Stem I n f l o r e s c e n c e I n v o l u c r e R e c e p t a c l e H_. k a l m i i L, Lepage 1960 not s c a b r o u s upper l e a v e s rounded t o c u n e a t e a t base b r a c t s 10 t o 15 mm l o n g , l a n c e -a t t e n u a t e - 14 -e a s t e r n N o r t h A m e r i c a , Europe and Asia.was a l s o o b t a i n e d . D i s t r i b u t i o n o f t h e c o l l e c t i o n s examined i s shown on t h e maps i n F i g u r e s 2 and 3. Each p l o t t e d p o i n t r e p r e s e n t s one h e r b a r i u m s h e e t (sometimes more th a n one s p e c i m e n ) . The f o l l o w i n g c h a r a c t e r s were r e c o r d e d : (1) abundance o f s u b c o n i c h a i r s on l e a f margins (2) abundance o f l o n g s p r e a d i n g h a i r s on stem base (3) l e a f l e n g t h and w i d t h (4) pubescence on i n v o l u c r e ( i f any) (5) i n d e n t a t i o n o f l e a f m a r g i n (6) number o f f l o w e r heads The s u b c o n i c h a i r s were measured on two d i f f e r e n t upper l e a v e s and t h e r e s u l t s a v e r a g e d . These h a i r s v a r y i n l e n g t h , some b e i n g s c a r c e l y as l o n g as t h e y a r e wide w h i l e o t h e r s a r e s i x o r seven t i m e s l o n g e r t h a n they a r e wide. S i z e i s c o n s i s t e n t on a g i v e n specimen. Length o f t h e s u b c o n i c h a i r s t e n d s t o be d i r e c t l y c o r r e l a t e d w i t h abundance, a t l e a s t i n t h e specimens examined. In a g i v e n i n d i v i d u a l t h e s e h a i r s a r e more p l e n t i f u l on t h e upper l e a v e s ; on t h e lowermost l e a v e s t h e y o c c a s i o n a l l y d i s a p p e a r a l t o g e t h e r , o r a r e r e p l a c e d by l o n g s p r e a d i n g h a i r s . L e a f l e n g t h and w i d t h measurements were t a k e n from t h e two l e a v e s n e a r e s t t h e m i d d l e o f t h e stem ( o f t e n t h e l a r g e s t l e a v e s ) . The r e m a i n i n g c h a r a c t e r s (pubescence o f i n v o l u c r e and stem, and t o o t h i n g o f l e a f m a r g i n ) were e s t i m a t e d s u b j e c t i v e l y . The r e s u l t s a r e g i v e n i n t h e f o r m o f s c a t t e r diagrams i n F i g u r e s 4 t o 7. S e p a r a t e diagrams were drawn up f o r w e s t e r n N o r t h America and f o r o t h e r r e g i o n s . F i g u r e s 4 and 5 show t h e range o f v a r i a t i o n i n l e a f s i z e . - 16 -F i g u r e 3. The H i e r a c i u m umbellatum complex: c o l l e c t i o n s i t e s o f a l l m a t e r i a l examined f r o m o t h e r r e g i o n s .  - 17 -4. L e a f l e n g t h - t o - w i d t h r a t i o s i n t h e H i e r a c i u m umbellatum complex • i n w e s t e r n N o r t h A m e r i c a . CM, III II / / f 4/ i / • • / / / ; / / • • • '* /• * */ '• 'lit** / •* / . / / ' • / " . / ... - -... •.. / / ' *• : s * : %. 1 I ,/C /. j •.% : r . / . . . ••> / • • T hi! /•• o i i : /•• y./.. . / // / / // / "/ / / / ' ' v y 1.0 2.0 L e a f w i d t h , cm 3.0 4.0 5.0 - 18 -F i g u r e 5. L e a f l e n g t h - t o - w i d t h r a t i o s i n t h e H i e r a c i u m umbellatum complex i n Europe, A s i a and e a s t e r n N o r t h A m e r i c a . 15.0 14.0 13.0 12.0 11.0 10.0 9.0 8.0 7.0 CD c CD - 6.0 (C CD 5.0 4.0 3.0 2.0 1.0 0 / « / 3 ' / / / / * / '/ / V V / ° / / °/ l I I I o / . / / / / ° / / II r. / " i ' /o / / . / / / / J , o V o 0 • • / o / 0/ / o / / • /. / I • • • / ' V / / / / I ? I" / / I. o . /o / ; / • I * / / o '•" 7 ' I I I / I " / / / / H_. umbellatum H. canadense / / / ° a • i i :i / \ / ./// o 1.0 2.0 3.0 L e a f w i d t h , cm 4.0 5.0 - 19 -The l e a f l e n g t h - t o - w i d t h r a t i o s used by C r o n q u i s t (1955a) and by G l e a s o n (1963) as a b a s i s f o r s e p a r a t i n g H i e r a c i u m umbellatum and H. canadense a r e i n d i c a t e d by d o t t e d l i n e s . A c c o r d i n g t o t h e d e f i n i t i o n s o f t h e s e a u t h o r s , most o f t h e p o i n t s p l o t t e d i n F i g u r e 4 f a l l w i t h i n t h e range f o r HL umbellatum (though a number o f t h e s e a r e i n t h e a r e a o f o v e r l a p w i t h JH. c a n a d e n s e ) . However, i f we assume t h a t t h e specimens whose l e a f measurements appear i n F i g u r e 5 a r e c o r r e c t l y i d e n t i f i e d , t h e l e a f l e n g t h -r t o - w i d t h r a t i o i s n o t a v e r y a c c u r a t e g u i d e t o s p e c i e s . The t e n d e n c y f o r H. umbellatum t o have narrower l e a v e s t h a n H_. canadense i s o n l y a v e r y g e n e r a l one, and t h e r e a r e many i n d i v i d u a l p l a n t s t h a t do not conform t o i t . The r e l a t i o n s h i p between l e a f l e n g t h - t o - w i d t h r a t i o , d e n s i t y o f s u b c o n i c h a i r s , and abundance o f l o n g s p r e a d i n g h a i r s on the stem base i s shown i n F i g u r e s 6 and 7. The range o f v a r i a t i o n i n each c h a r a c t e r and t h e r e l a t i v e f r e q u e n c y o f o c c u r r e n c e o f the d i f f e r e n t s t a t e s o f a c h a r a c t e r a r e a l s o e a s i l y s e e n . C l e a r l y t h e r e i s l i t t l e o r no c o r r e l a t i o n between any o f t h e c h a r a c t e r s examined h e r e . Two o t h e r l e s s c o n s p i c u o u s c h a r a c t e r s ( l e a f i n d e n t a t i o n , and d e n s i t y o f g l a n d u l a r h a i r s on t h e i n v o l u c r e ) a l s o f a i l e d t o show c o r r e l a t i o n s , e i t h e r w i t h one a n o t h e r o r w i t h t h e c h a r a c t e r s p r e v i o u s l y m e n t i o n e d , and a r e o m i t t e d from t h e diagram. I t can be seen t h a t l o n g h a i r s on t h e stem base t e n d t o be a s s o c i a t e d w i t h wide l e a v e s i n t h e m a t e r i a l from B r i t i s h C o l u m b i a , b u t t h i s t e n d e n c y i s much l e s s a p p a r e n t i n m a t e r i a l f r o m e l s e w h e r e . The e x p e c t e d c o r r e l a t i o n between h a i r i n e s s o f t h e stem and absence o f s u b c o n i c h a i r s does not o c c u r . F i g u r e 6. M o r p h o l o g i c a l v a r i a t i o n i n t h e H i e r a c i u m umbellatum complex i n w e s t e r n North A m e r i c a . Abundance o f l o n g h a i r s on base o f stem: *Z% • • • • • • # n o n e •*/ «^»* • • * few V # •f' moderate ( • . ^ dense |> tjfm^fo* 0 mj* • • • • • • • u c " i c 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Le a f l e n g t h - t o - w i d t h r a t i o o F i g u r e 7. M o r p h o l o g i c a l v a r i a t i o n i n t h e H i e r a c i u m umbellatum complex i n e a s t e r n North A m e r i c a , Europe and A s i a . o e a s t e r n N o r t h A m e r i c a • Europe and A s i a o • o o o o o a Abundance o f l o n g h a i r s on base o f stem: • none * few moderate dense o d O O °J—o ^ 5 6 7 8 9 10 11 12 13 14 15 16 17 L e a f l e n g t h - t o - w i d t h r a t i o 18 - 22 -I n t e r e s t i n g l y , a l m o s t a l l t h e m a t e r i a l examined f r o m w e s t e r n N o r t h America c l o s e l y resembles t y p i c a l H i e r a c i u m umbellatum (= s c a b r i u s c u l u m ) r a t h e r t h a n t y p i c a l H_. canadense. A l l specimens from t h i s a r e a p o s s e s s e d s u b c o n i c h a i r s on t h e l e a f margins (though i n some p l a n t s t h e s e were r e l a t i v e l y f e w ) . A c o m p a r i s o n o f T a b l e I w i t h F i g u r e s 6 and 7 i s i n f o r m a t i v e . T h e r e i s agreement among most r e c e n t a u t h o r s t h a t N o r t h American H_. umbellatum has s u b c o n i c h a i r s on the l e a f m a r g i n s , and u s u a l l y narrow l e a v e s ; jH. canadense l a c k s s u b c o n i c h a i r s and has w i d e r l e a v e s . Each o f t h e s e t y p e s v a r i e s w i t h r e s p e c t t o s e v e r a l o t h e r c h a r a c t e r s . I t i s e v i d e n t from t h e s c a t t e r d i a g r a m s , however, t h a t t h e r e i s l i t t l e d i f f e r e n c e i n t h e r e l a t i v e i m p o r t a n c e o f t h e v a r i o u s c h a r a c t e r s . C o n s e q u e n t l y , taxonomic d e c i s i o n s c o n c e r n i n g t h e numbers and l i m i t s o f t a x a have a l l been somewhat a r b i t r a r y . S i n c e t h e r e a r e no o b v i o u s m o r p h o l o g i c a l d i s c o n t i n u i t i e s t h i s a r b i t r a r i n e s s i s not e a s i l y a v o i d e d . However, an awareness o f t h e problem may p r e v e n t h e e d l e s s p r o l i f e r a t i o n o f s p e c i e s and v a r i e t i e s . F o r example, Lepage (1958, 1960, 1961, 1971), whose knowledge o f t h e morphology o f N o r t h American E u h i e r a c i u m i s e x t e n s i v e but whose taxonomic t r e a t m e n t o f t h e group i s s t r i c t l y c l a s s i c a l , has s e p a r a t e d HL s c a b r i u s c u l u m i n t o f i v e v a r i e t i e s and jH. canadense i n t o f o u r , on t h e b a s i s o f minute d i f f e r e n c e s i n pubescence o f l e a v e s o r stem. A l s o o f c o n s i d e r a b l e i n t e r e s t i n F i g u r e s 6 and 7 i s t h e e v i d e n t o v e r a l l s i m i l a r i t y between p l a n t s from d i f f e r e n t p a r t s o f t h e w o r l d . The l e a f l e n g t h - t o - w i d t h r a t i o i s v e r y s i m i l a r i n t h e e a s t e r n and w e s t e r n p a r t s o f - 23 -t h i s c o n t i n e n t . The range o f v a r i a t i o n i n the O l d W o r l d , however, i s much g r e a t e r t h a n i n N o r t h A m e r i c a , s i n c e i n some o f t h e p l a n t s from t h e s e a r e a s t h e l e a v e s a r e e x t r e m e l y narrow. A s i n g l e specimen ( n o t shown i n F i g u r e 6) f r o m Tomsk i n t h e U. S. S. R. had a l e a f l e n g t h - t o - w i d t h r a t i o o f 36.5, but t h i s i s e x c e p t i o n a l . Of t h e s e v e r a l a u t h o r s (Rydberg 1922, Lepage 1958 and 1960, H u l t S n 1968) who r e g a r d H_. s c a b r i u s c u l u m Schwein. as s e p a r a t e from t h e European H_. umbel!atum L., o n l y Lepage (1958) o f f e r s any d i s c u s s i o n o f how t h e s e two s p e c i e s d i f f e r . Lepage d e s c r i b e s H_. s c a b r i u s c u l u m as h a v i n g s t i f f e r l e a v e s , more r e v o l u t e l e a f m a r g i n s , more abundant s u b c o n i c h a i r s , and w i d e r i n v o l u c r a l b r a c t s than H_. umbellatum. However, i n F i g u r e s 6 and 7 i t can be seen t h a t f o r t h o s e c h a r a c t e r s measured i n t h e p r e s e n t s t u d y , t h e range o f v a r i a t i o n shown f o r t h e European m a t e r i a l a l m o s t c o m p l e t e l y encompasses t h a t found i n N o r t h A m e r i c a . Even f a i r l y t y p i c a l specimens o f _H. canadense ( r e p r e s e n t e d i n F i g u r e 7 by open c i r c l e s a l o n g t h e a b c i s s a ) c l o s e l y resemble two p l a n t s o f European H_. umbellatum. The l a t t e r s p e c i e s i s so v a r i a b l e i n t h e O l d World t h a t t h e r e seems t o be l i t t l e j u s t i f i c a t i o n f o r c l a s s i f y i n g N o r t h American m a t e r i a l as a s e p a r a t e s p e c i e s ; t h e range o f d i f f e r e n c e s w i t h i n each c o n t i n e n t i s much g r e a t e r t h a n t h e a v e r a g e d i f f e r e n c e between t h e two c o n t i n e n t s . The d i s c o v e r y o f a d d i t i o n a l ( f o r example chromosomal) d i f f e r e n c e s might j u s t i f y s e p a r a t i o n a t t h e s u b s p e c i e s o r v a r i e t a l l e v e l , once t h e e x t e n t o f v a r i a b i l i t y i n Europe has been d e t e r m i n e d . The c o m b i n a t i o n H_. umbellatum v a r . s c a b r i u s c u l u m was p u b l i s h e d by F a r w e l l i n 1927, but h i s specimen was e v i d e n t l y much c l o s e r t o H_. canadense t h a n t o N o r t h American H_. umbellatum. I t i s i n t e r e s t i n g t h a t t h e t y p e specimen o f - 24 -H_. s c a b r i u s c u l u m , c o l l e c t e d n e a r Lake Winnipeg i n 1823 and d e s c r i b e d i n 1824, has s u b c o n i c h a i r s but a l s o wide, c l a s p i n g l e a v e s . I t was e v i d e n t l y an i n t e r m e d i a t e between JH. canadense and JH. umbellatum as d e s c r i b e d by C r o n q u i s t (1955a). F i g u r e 8 shows t h e d i s t r i b u t i o n o f numbers o f f l o w e r heads per p l a n t f o r a l l t h e specimens o f t h e JH. umbellatum complex t h a t were examined. In B r i t i s h Columbia t h e most f r e q u e n t l y e n c o u n t e r e d number i s f i v e , though much h i g h e r numbers o f f l o w e r heads have been found on s c a t t e r e d i n d i v i d u a l s . A number o f e a r l y a u t h o r s a t t e m p t e d t o make use o f number o f f l o w e r heads and t y p e o f i n f l o r e s c e n c e , t o s e p a r a t e H_. umbellatum and Jj_. c anadense. Gray (1888) and Henry (1915) d e s c r i b e H. canadense as h a v i n g many f l o w e r heads, a r r a n g e d i n a p a n i c l e o r p a n i c u l a t e cyme. However, Michaux (1803) and Rydberg (1901) d e s c r i b e i t as f e w - f l o w e r e d ( t h e t y p e specimen has t h r e e stems w i t h one, two and e i g h t f l o w e r heads r e s p e c t i v e l y ) . C r o n q u i s t (1955a) d e s c r i b e s H. umbel!atum as many-flowered (heads u s u a l l y 40 t o 110). I t i s c l e a r from t h e g r a p h , however, t h a t none o f t h e s e d i s t i n c t i o n s have any taxonomic v a l u e . The number o f f l o w e r heads p r o b a b l y depends m a i n l y on growing c o n d i t i o n s . The H i e r a c i u m s c o u l e r i complex and H i e r a c i u m a l b i f l o r u m . H i e r a c i u m a l b i f l o r u m i n t e r b r e e d s w i t h t h e s p e c i e s o f the H_. s c o u l e r i complex ( s e e C h a p t e r I I I ) , c l o s e l y r e s e m b l e s them i n g e n e r a l h a b i t , and i s s c a r c e l y d i s t i n g u i s h a b l e from them when not i n f l o w e r ( e x c e p t f o r m i c r o m o r p h o l o g i c a l . c h a r a c t e r s ) . I t i s t h e r e f o r e i n c l u d e d h e r e . V a r i a b i l i t y o f m o r p h o l o g i c a l c h a r a c t e r s i s d i s c u s s e d s e p a r a t e l y f o r t h e JH. s c o u l e r i - 25 -F i g u r e 8. Numbers o f f l o w e r heads i n t h e H i e r a c i u m umbellatum complex. H. canadense from e a s t e r n N o r t h America X L so 10 H_. umbellatum from e a s t e r n N o r t h A m e r i c a , Europe and A s i a n n 30 to 50 3? 30h Specimens from w e s t e r n N o r t h America to E <a Q-4 -O J3 Lr L q n n , r X I n . , . . n so 20 30 HO Number o f f l o w e r heads p e r p l a n t - 26 -group, f o r JH. a l b i f l o r u m , and f o r t h e two groups t o g e t h e r . (1) V a r i a t i o n w i t h i n the H i e r a c i u m s c o u l e r i complex. The t h r e e s p e c i e s c o n s i d e r e d h e r e a r e m o r p h o l o g i c a l l y v e r y s i m i l a r and a r e s e p a r a t e d a l m o s t e n t i r e l y by d i f f e r e n c e s i n p u b e s c e n c e , a f a c t f i r s t p o i n t e d o u t by P i p e r (1906). A c c o r d i n g t o C r o n q u i s t (1955a), t y p i c a l H_. a l b e r t i n u m F a r r i s d e n s e l y c o v e r e d t h r o u g h o u t w i t h l o n g w h i t e s e t o s e h a i r s . H i e r a c i u m c y n o g l o s s o i d e s Arv.-Touv. has h a i r s on the f o l i a g e but few t o none on t h e i n v o l u c r e , and H_. s c o u l e r i Hook, has a few s e t o s e h a i r s on t h e lowermost l e a v e s ( o r sometimes no s e t o s e h a i r s a t a l l ) . C r o n q u i s t mentions t h e i n t e r g r a d a t i o n between t h e s e t h r e e s p e c i e s , and the p r e s e n t s t u d y c o n f i r m s i t . H i e r a c i u m s c o u l e r i was the f i r s t o f t h e t h r e e t o be d e s c r i b e d (Hooker 1833). H i e r a c i u m c y n o g l o s s o i d e s was d e s c r i b e d i n 1881 and HL a l b e r t i n u m not u n t i l 1906. E a r l y f l o r a s on w e s t e r n N o r t h America added t h e s e names as t h e y a p p e a r e d , g i v i n g t h e i m p r e s s i o n t h a t new m o r p h o l o g i c a l e n t i t i e s were b e i n g d i s c o v e r e d . However, i t i s c l e a r f r o m t h e v a r i a b i l i t y encompassed by t h e d e s c r i p t i o n s t h a t some a u t h o r s a t l e a s t ( T o r r e y & Gray 1843, Gray 1888) had a l r e a d y e n c o u n t e r e d most o r a l l o f t h e v a r i a n t s t h a t a r e p r e s e n t l y known. In t h i s s t u d y , a p p r o x i m a t e l y 200 specimens were examined, o f w h i c h about 60 were t a k e n from a s i n g l e l o c a l i t y t w e l v e m i l e s n o r t h o f L y t t o n , B r i t i s h C olumbia. The d i s t r i b u t i o n o f specimens examined i s mapped i n F i g u r e 9. A l t h o u g h a l l t h e s p e c i e s d i s c u s s e d here e x t e n d as f a r s o u t h as - 28 -Oregon o r C a l i f o r n i a , o n l y a few American specimens were a v a i l a b l e f o r i n s p e c t i o n . The r e s u l t s a r e t h e r e f o r e somewhat i n c o m p l e t e , and some m o r p h o l o g i c a l v a r i a n t s known t o e x i s t were not i n c l u d e d ( e . g . H i e r a c i u m  s c o u l e r i v a r . n u d i c a u l e (Cronq.) G r a y ) . The number o f f l o w e r heads and the t y p e and d e n s i t y o f pubescence on i n v o l u c r e , stem and l e a v e s was r e c o r d e d f o r each specimen. T h r e e t y p e s o f pubescence were measured: s t e l l a t e h a i r s , g l a n d u l a r h a i r s , and l o n g s e t o s e h a i r s . The g l a n d u l a r and s t e l l a t e h a i r s a r e m i n u t e and i n c o n s p i c u o u s . They were measured a t the base o f t h e i n v o l u c r e , where t h e y a r e most abundant. Both t y p e s o f h a i r s were p r e s e n t i n a l l specimens examined. G l a n d u l a r h a i r s v a r i e d i n d e n s i t y from one o r two t o t e n o r f i f t e e n h a i r s p e r s q u a r e m i l l i m e t e r , and t h e r e was no c o r r e l a t i o n w i t h t h e d e n s i t y o f l o n g s e t o s e h a i r s . S t e l l a t e h a i r s a r e d i s c u s s e d on page 36. D e n s i t y o f t h e l o n g s e t o s e h a i r s (which a r e w h i t e i n l i v e p l a n t s but become y e l l o w on d r y i n g ) was measured on two o f the lower c a u l i n e l e a v e s o f each specimen. " R e p r e s e n t a t i v e " l e a v e s ( o f a v e r a g e age and p u bescence) were s e l e c t e d as f a r as p o s s i b l e . Both s i d e s o f each l e a f were measured, and h a i r d e n s i t y was u s u a l l y t h e same above and b e n e a t h , o r sometimes s l i g h t l y g r e a t e r beneath. The v a r i a t i o n i n d e n s i t y o f s e t o s e h a i r s i s shown i n F i g u r e 10. D e n s i t i e s o f t h e s e h a i r s on i n v o l u c r e and on l e a v e s a r e somewhat c o r r e l a t e d . A l l specimens w i t h h a i r s on t h e i n v o l u c r e have h a i r y l e a v e s a l s o , a l t h o u g h specimens l a c k i n g a h a i r y i n v o l u c r e may o r may n o t have h a i r s on t h e l e a v e s . I t i s c l e a r f r o m t h e d i a g r a m t h a t v a r i a t i o n between t h e two extremes o f H. a l b e r t i n u m and H. s c o u l e r i i s - 29 -F i g u r e 10. M o r p h o l o g i c a l v a r i a t i o n i n t h e H i e r a c i u m s c o u l e r i complex. 35 s-OJ - O E QJ i-o O > o s-n3 V) O +-> OJ (/) o >> 4-> Q 30 25 20 15 10 s ^ ^ — 0 1 2 3 4 D e n s i t y o f s e t o s e h a i r s on lower l e a v e s (number/mm 2) - 30 -more o r l e s s c o n t i n u o u s and t h a t t h e d i v i s i o n s between s p e c i e s a r e l a r g e l y a r b i t r a r y . I have o b s e r v e d t h a t H^ . s c o u l e r i d i f f e r s from t h e o t h e r two s p e c i e s e c o l o g i c a l l y as w e l l as m o r p h o l o g i c a l l y . T h i s e c o l o g i c a l d i f f e r e n c e was most pronounced i n t h e c o m p l e t e l y g l a b r o u s s p e c i m ens; pubescence app e a r s t o be c o r r e l a t e d w i t h h a b i t a t . H i e r a c i u m a l b e r t i n u m and H_. c y n o g l o s s o i d e s f r e q u e n t l y o c c u r t o g e t h e r i n q u i t e d r y h a b i t a t s . They were o b s e r v e d i n a l p i n e meadows o f t h e I n t e r i o r S u b a l p i n e Zone and d r y woods o f t h e Ponderosa P i n e - B u n c h g r a s s Zone o f K r a j i n a (1959). H i e r a c i u m s c o u l e r i a p p a r e n t l y p r e f e r s damper s i t e s , and when found i n t h e same l o c a l i t y as t h e o t h e r two s p e c i e s i t o c c u r s i n c o o l e r , more shaded h a b i t a t s . K r a j i n a c o n s i d e r s i t a c h a r a c t e r i s t i c s p e c i e s i n w e t t e r p a r t s o f t h e I n t e r i o r S u b a l p i n e Zone and i n t h e A l p i n e Zone. C r o n q u i s t (1955a.) mentions t h a t H_. s c o u l e r i i s more commonly e n c o u n t e r e d i n t h e Cascade M o u n t a i n s , and the o t h e r two s p e c i e s more o f t e n e a s t w a r d . In F i g u r e 11 t h e number o f f l o w e r heads p e r p l a n t i s p l o t t e d f o r each o f t h e t h r e e s p e c i e s and f o r the combined t o t a l . The a v e r a g e s f o r t h e t h r e e s p e c i e s a r e s l i g h t l y d i f f e r e n t ( s m a l l e s t i n H_. a l b e r t i n u m and l a r g e s t i n H_. s c o u l e r i ) but t h e o v e r a l l r a n ges o f v a r i a t i o n a r e v e r y s i m i l a r . (2) V a r i a t i o n i n H i e r a c i u m a l b i f l o r u m . T h i s s p e c i e s i s not c o n s p i c u o u s l y v a r i a b l e a l t h o u g h i t i s common i n w e s t e r n N o r t h A m e r i c a , p a r t i c u l a r l y i n s u c c e s s i o n a l h a b i t a t s . Zahn (1922) s e p a r a t e s i t i n t o s e v e r a l v a r i e t i e s and f o r m s , but i s t h e o n l y a u t h o r t o - 31 -F i g u r e 11. Numbers o f f l o w e r heads i n s p e c i e s o f t h e H i e r a c i u m s c o u l e r i complex. is 10 J l 1 a H. a l b e r t i n u m 10 20 30 to 10 o 10 H_. c y n o g l o s s o i d e s l r H n r—i n . 10 20 to +-> E n i l ra 0 TT 30, I 25r 3 30 H. s c o u l e r i 10 10 20 (5 10 0 Combined t o t a l f l j i l h . lo 2o 3 0 Number o f f l o w e r heads per p l a n t HO n 50 50 }n n H i n 11 f h n ,.. f 20 30 tO 50 S'O - 32 -do so. H i e r a c i u m a l b i f l o r u m Hook, has l o n g s e t o s e h a i r s on the f o l i a g e , as do t h e members o f t h e H_. s c o u l e r i complex, and i t s g e n e r a l a p p e a r a n c e i s v e r y s i m i l a r t o t h a t o f H. c y n o g l o s s o i d e s . About 150 specimens were examined; t h e i r d i s t r i b u t i o n i s p l o t t e d i n F i g u r e 12. The r e l a t i o n s h i p between t h e d i f f e r e n t t y p e s o f pubescence i n H_. a l b i f l o r u m i s shown i n F i g u r e 13. As w e l l as s e t o s e h a i r s on t h e f o l i a g e and sometimes on t h e i n v o l u c r e , t h e r e a r e u s u a l l y some minute g l a n d u l a r h a i r s (much s m a l l e r t h a n t h o s e found i n t h e H. s c o u l e r i complex) on the i n v o l u c r e . These c h a r a c t e r s a l l v a r y i n d e p e n d e n t l y . The v a r i a t i o n i n numbers o f f l o w e r heads p e r p l a n t i n t h i s s p e c i e s i s shown i n F i g u r e 14. A l t h o u g h the most commonly e n c o u n t e r e d number o f f l o w e r heads on a p l a n t was e i g h t , t h e a v e r a g e number (21) was much h i g h e r because t h e o c c a s i o n a l i n d i v i d u a l f r o m a f a v o u r a b l e s i t e was a b l e t o produce more th a n 100 heads. T h i s t e n d e n c y t o f l o w e r w e l l i s most n o t i c e a b l e i n c u l t i v a t e d s pecimens. In p l a n t s grown from seed f o r c r o s s i n g e x p e r i m e n t s (see C h a p t e r I I I ) , many produced 50 heads o r more, a l t h o u g h t h e p a r e n t p l a n t s f r e q u e n t l y had few f l o w e r heads. (3) The r e l a t i o n s h i p between t h e H i e r a c i u m s c o u l e r i complex and Jj_. a l b i f l o r u m . H i e r a c i u m a l b i f l o r u m i s most r e a d i l y d i s t i n g u i s h e d from s p e c i e s o f t h e H_. s c o u l e r i complex by t h e c o l o u r o f i t s f l o w e r s . Specimens n o t i n f l o w e r a r e e a s i l y c o n f u s e d w i t h t h e l a t t e r g r o u p , but t h e y can be d i s t i n g u i s h e d by o t h e r l e s s c o n s p i c u o u s (and sometimes l e s s c o n s i s t e n t ) d i f f e r e n c e s . The f l o w e r heads o f IK. a l b i f l o r u m a r e narrower t h a n t h o s e o f t h e JH_. s c o u l e r i group, l e a v i n g a s m a l l e r r e c e p t a c l e s u r f a c e a f t e r t h e - 34 -F i g u r e 13. M o r p h o l o g i c a l v a r i a t i o n i n H i e r a c i u m a l b i f l o r u m . V MT • • • • •• • Abundance o f l o n g h a i r s on i n v o l u c r e : • none •c few J moderate 1 2 3 4 D e n s i t y o f s e t o s e h a i r s on f o l i a g e (number/mm 2) - 35 -F i g u r e 14. V a r i a t i o n i n numbers o f f l o w e r heads i n H i e r a c i u m a l b i f l o r u m . 1.0 r n3 IOr 10 20 50 n E Z L HO n 50 4— O S-XI O IOr 60 n , n . , n .,. n n . n no 80 90 100 n . • • n no I20 130 150 Number o f f l o w e r heads per p l a n t - 36 -seeds a r e shed. The l e a v e s a r e o f t e n w a v y - d e n t i c u l a t e ( w i t h s m a l l , w i d e l y -spaced t e e t h ) w h i l e t h o s e o f the members o f the H i e r a c i u m s c o u l e r i group a r e e n t i r e . H i e r a c i u m a l b i f l o r u m o f t e n has a r e d d i s h stem, and l e a v e s exposed t o f r o s t f r e q u e n t l y d e v e l o p a n t h o c y a n i n c o l o r a t i o n as w e l l . T h i s i s n o t seen i n the H_. s c o u l e r i complex. A t most, the l a t t e r has a t i n g e o f r e d a t the v e r y base o f t h e stem. D i f f e r e n c e s i n numbers o f f l o w e r heads a r e n o t i c e a b l e i n the l a r g e s t p l a n t s o f each group (compare F i g u r e s 11 and 1 4 ) . The l a r g e s t p l a n t t h a t I examined from t h e H_. s c o u l e r i group had f i f t y f l o w e r heads, whereas s e v e r a l specimens o f H_. a l b i f l o r u m had two o r t h r e e t i m e s as many. In h y b r i d s between JH_. a l b i f l o r u m and any s p e c i e s o f t h e H_. s c o u l e r i complex, the i n f l u e n c e o f the former on s i z e o f i n f l o r e s c e n c e can c l e a r l y be seen. Another d i f f e r e n c e between the two groups i s i n the g l a n d u l a r h a i r s t h a t o c c u r on the i n v o l u c r e s o f a l l t he s p e c i e s . In JH. a l b i f l o r u m t h e s e a r e minute and y e l l o w ; i n s p e c i e s o f the H_. s c o u l e r i complex t h e y a r e y e l l o w t o y e l l o w i s h - b l a c k , and a r e two t o t h r e e t i m e s as l a r g e . None o f the d i f f e r e n c e s d i s c u s s e d so f a r a r e d i a g n o s t i c . However, one d i f f e r e n c e which ap p e a r s t o be r e l i a b l e , and i s used by C r o n q u i s t (1.955a) t o s e p a r a t e t h e two g r o u p s , i s t h e p r e s e n c e o r absence o f s t e l l a t e h a i r s . A l t h o u g h t h e s e h a i r s a r e s m a l l and i n c o n s p i c u o u s , t h e y a ppear t o be an a c c u r a t e i n d i c a t o r o f s p e c i e s . A t a b u l a t i o n o f the d e n s i t i e s o f s t e l l a t e h a i r s i n a l l f o u r s p e c i e s i s p r e s e n t e d i n F i g u r e 15. H a i r d e n s i t y was s u b j e c t i v e l y e s t i m a t e d on t h e - 37 -F i g u r e 15. R e l a t i v e abundance o f s t e l l a t e h a i r s i n H i e r a c i u m a l b i f l o r u m and i n the H i e r a c i u m s c o u l e r i complex. 150 20 10 0 "40 30 20 10 0 •20 10 H. albertinum _H_. cynogloss3ides H. scbuleri The H i e r a c i u m s c o u l e r i complex CO c_> CD UU CO H- cn LU -d-d: CO CCD. ctr LU co Q_ CD CO s 1 CO LU cn ac i_u LU LU CD CD CD 140 130 120 no 100 90 80 70 60 50 40 30 20 10 H i e r a c i u m a l b i f l o r u m CD o i — cn LU LU GO LU en D e n s i t y o f s t e l l a t e h a i r s - 38 -i n v o l u c r e o f each specimen. In some specimens t h e h a i r s were s u f f i c i e n t l y dense t o o b s c u r e t he s u r f a c e beneath. E v e r y p l a n t t h a t was examined i n the JH. s c o u l e r i group p o s s e s s e d s t e l l a t e h a i r s , and a l m o s t e v e r y specimen o f JH_. a l b i f l o r u m l a c k e d them. However, i n some members o f t h e fo r m e r group t h e s e h a i r s (though p r e s e n t ) were r e l a t i v e l y few; i n a few p l a n t s o f JH_. a l b i f l o r u m s t e l l a t e h a i r s were p r e s e n t . C l e a r l y t h e r e i s some o v e r l a p between the two groups. D e a r d o r f f ( 1 9 7 4 ) , i n h i s r e c e n t work on t h e subgenus S t e n o t h e c a i n western N o r t h A m e r i c a , c l a i m s t h a t c o n s i d e r a b l e h y b r i d i z a t i o n has o c c u r r e d between H_. a l b i f l o r u m and t h e JH. s c o u l e r i complex and t h a t t h i s has had a s i g n i f i c a n t i n f l u e n c e on H. s c o u l e r i . I can f i n d no m o r p h o l o g i c a l e v i d e n c e t h a t t h e i n d i v i d u a l s n o r m a l l y grouped under t he name JH_. s c o u l e r i a r e t h e r e s u l t o f h y b r i d i z a t i o n between the members o f the JH_. s c o u l e r i group and JH. a l b i f l o r u m , o r t h a t i n t r o g r e s s i o n by H_. a l b i f l o r u m i s s i g n i f i c a n t l y g r e a t e r i n H_. s c o u l e r i than i n the o t h e r two s p e c i e s o f t h e group. From the i n s e t i n F i g u r e 15 i t i s a p p a r e n t t h a t H_. s c o u l e r i shows no t e n d e n c y toward t h e l a c k o f s t e l l a t e h a i r s t y p i c a l o f H. a l b i f l o r u m . I t i s t r u e , however, t h a t Fx h y b r i d s between the two groups a r e e a s i l y c o n f u s e d w i t h t h e i r y e l l o w - f l o w e r e d p a r e n t . Because o f t h i s , b a c k c r o s s e s o f t h e h y b r i d t o members o f the JH. s c o u l e r i complex would be d i f f i c u l t t o i d e n t i f y . However, b a c k c r o s s e s t o H_. a l b i f l o r u m a r e e a s i l y d e t e c t e d by t h e i r f l o w e r c o l o u r , and s e v e r a l such p l a n t s were i d e n t i f i e d d u r i n g t h i s s t u d y ( s e e Ch a p t e r I I I ) . The o c c u r r e n c e o f s t e l l a t e h a i r s on p l a n t s which a r e o t h e r w i s e t y p i c a l specimens o f H_.. a l b i f l o r u m c o u l d be i n t e r p r e t e d as an i n d i c a t i o n o f i n t r o g r e s s i o n o f the s p e c i e s o f the JH. s c o u l e r i complex i n t o H_. a l b i f l o r u m . - 39 -The H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e Complex. The combined ranges o f JH. t r i s t e W i l l d . and H_. g r a c i l e Hook, e x t e n d from t h e A l e u t i a n I s l a n d s and s o u t h e r n A l a s k a t o C a l i f o r n i a and New Mexico, and d i s j u n c t l y t o the C h i l e a n Andes. These two t a x a d i f f e r m a i n l y i n t y p e and d e n s i t y o f pubescence on the i n v o l u c r e . T h e r e i s d i s a g r e e m e n t on whether the i n t e r g r a d a t i o n between them j u s t i f i e s t h e i r c o m b i n a t i o n i n t o a s i n g l e s p e c i e s , o r whether t h e y a r e b e t t e r t r e a t e d as two. A number o f a u t h o r s , i n c l u d i n g P o r s i l d (1950 and 1951), Hult£n (1960, 1968, 1973) and Welsh (1974) among o t h e r s , have r e g a r d e d t h e s e two ta x a as s e p a r a t e s p e c i e s ; however, Gray (1876) and C a l d e r & T a y l o r (1968) combined them under t h e name H_. t r i s t e ( a l t h o u g h Gray (1888) l a t e r s e p a r a t e d them a g a i n ) . S e v e r a l v a r i e t i e s have been proposed by a u t h o r s o f the f i r s t - m e n t i o n e d group, e s p e c i a l l y w i t h i n H_. g r a c i l e , to de a l w i t h i n t e r m e d i a t e forms. Some o f t h e s e may be o f v a l u e w h i l e o t h e r s c l e a r l y a r e n o t . In t h i s s t u d y , between 400 and 500 specimens were examined. The d i s t r i b u t i o n o f t h e s e i s shown i n F i g u r e 16. R e l a t i v e l y few specimens were examined f r o m the s o u t h e r n p a r t o f the r a n g e , b ut t h o s e t h a t were seen resembled c l o s e l y t h e m a t e r i a l from s o u t h e r n B r i t i s h Columbia. On t h e b a s i s o f the r e s u l t s p r e s e n t e d h e r e , t h e a p p r o x i m a t e ranges o f the two t a x a have been i n d i c a t e d on t h e map. W i t h i n t h e r e g i o n o f o v e r l a p , c o n s i d e r a b l e .. v a r i a t i o n i n morphology may o c c u r a t a s i n g l e s i t e . Each specimen was examined f o r d e n s i t y o f pubescence on the i n v o l u c r e , o c c u r r e n c e o f l o n g p i l o s e h a i r s on t h e l e a v e s , and number o f f l o w e r heads. H a i r d e n s i t i e s were a s s e s s e d u s i n g a d i s s e c t i n g m i c r o s c o p e w i t h c a l i b r a t e d - 41 -e y e p i e c e . The r e s u l t i n g d a t a i s p r e s e n t e d i n F i g u r e 17. H a i r s o c c u r r i n g on t h e i n v o l u c r e a r e o f t h r e e t y p e s : l o n g g r a y p i l o s e h a i r s (2-5 mm i n l e n g t h ) , b l a c k g l a n d u l a r h a i r s ( a p p r o x i m a t e l y 0.5 mm i n l e n g t h ) , and s h o r t , w h i t e , c o n v o l u t e d s t e l l a t e h a i r s . The s t e l l a t e h a i r s v a r y i n abundance from moderate t o v e r y dense but t h i s v a r i a t i o n i s o f no taxonomic v a l u e . The o t h e r two h a i r t y p e s v a r y i n d e n s i t y more o r l e s s i n v e r s e l y w i t h one a n o t h e r . When t h e y o c c u r t o g e t h e r on a g i v e n p l a n t , t h e y a r e u s u a l l y accompanied by some h a i r s o f i n t e r m e d i a t e t y p e ( b l a c k , n o n g l a n d u l a r , and about 1 mm l o n g ) . The s c a t t e r d i a g r a m shows a more o r l e s s b i p o l a r d i s t r i b u t i o n o f m o r p h o l o g i c a l t y p e s . Most i n d i v i d u a l s f a l l i n t o one o f two c l u s t e r s ; s c a t t e r e d around them a r e specimens o f the l e s s common phases. Of the two common m o r p h o l o g i c a l t y p e s , one (JH. t r i s t e ) i s d e n s e l y c o v e r e d on the i n v o l u c r e w i t h l o n g g r a y p i l o s e h a i r s , has no g l a n d u l a r h a i r s , and has s l i g h t l y h a i r y l e a v e s . The o t h e r (jj_. g r a c i l e ) has moderate t o dense g l a n d u l h a i r s on the i n v o l u c r e and few t o many, somewhat s h o r t e r , g r a y t o b l a c k p i l o s e h a i r s . I t has no l o n g h a i r s on the l e a v e s . The names t r i s t e v a r . t r i s t i f o r m e Zahn and H_. g r a c i l e v a r . alaskanum Zahn have been a p p l i e d t o the forms i n t e r m e d i a t e between t h e two s p e c i e s . These pass i n t o one a n o t h e r , as w e l l as i n t o the t y p i c a l phases o f H_. t r i s t e and H_. g r a c i l e r e s p e c t i v e l y . The extreme o f H_. g r a c i l e which l a c k s a l l l o n g , n o n g l a n d u l a r h a i r s ( r e f e r a b l e to v a r . detonsum Gray) i s n o t as common as was e x p e c t e d . The l e n g t h o f t h e l o n g g r a y p i l o s e h a i r s i s p o s i t i v e l y c o r r e l a t e d w i t h t h e i r d e n s i t y . Some specimens o f H_. t r i s t e produce such dense, l o n g wool F i g u r e 17. M o r p h o l o g i c a l v a r i a t i o n i n the H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e complex. 25 r 20 h 6 15 10 (pOO 66o q>6. 6 6 66 66 6.6 66 6 & 6 6 6 6 66 o 6 6 6 Abundance o f h a i r s on l e a v e s O none o s c a t t e r e d O — moderate Length o f p i l o s e h a i r s : o 1 mm 6 3 mm O 5 mm 5 10 15 20 25 D e n s i t y o f g r a y - b l a c k p i l o s e h a i r s (number/mm 2) 30 35 - 43 -t h a t t h e i n v o l u c r e s a r e w i d e r than t h e s p r e a d o f the r a y f l o w e r s , and t h e i r a p pearance i s v e r y s t r i k i n g . Such p l a n t s u s u a l l y have p u b e s c e n t f o l i a g e ( t h e h a i r s b e i n g most abundant on t h e c a u l i n e and y o u n g e s t b a s a l l e a v e s ) . Some a u t h o r s ( e . g . , P o r s i l d 1951) c o n s i d e r H i e r a c i u m g r a c i l e t o have more p o i n t e d l e a v e s than H. t r i s t e , t h o s e o f t h e l a t t e r s p e c i e s b e i n g t y p i c a l l y s p a t u l a t e . No e v i d e n c e o f t h i s d i f f e r e n c e was found i n the p r e s e n t s t u d y . The l e a v e s t e n d t o be most s p a t u l a t e a t the v e r y base, i n both o f the s p e c i e s . The newer l e a v e s a r e l e s s s o , and the s m a l l l e a f n o r m a l l y p r e s e n t on the stem i s u s u a l l y a c u t e . The shape o f b a s a l l e a v e s p r o b a b l y depends on the number o f l e a v e s r e t a i n e d on the p l a n t , which i s under t he i n f l u e n c e o f growing d o n d i t i o n s . A l l p l a n t s examined i n t h i s s t u d y showed c o n s i d e r a b l e v a r i a t i o n i n h a i r d e n s i t y , both w i t h i n a s i n g l e i n v o l u c r e and between one f l o w e r head and t h e ne x t . I n v o l u c r e s were measured n e a r t h e i r base ( i n t h e r e g i o n o f g r e a t e s t h a i r d e n s i t y ) , and an e f f o r t was made t o a r r i v e a t an av e r a g e v a l u e based on i n s p e c t i o n o f s e v e r a l i n v o l u c r e s f o r each p l a n t . Human e r r o r ( i n t h e form o f a te n d e n c y t o round o f f e s t i m a t e s ) l e d t o a cl u m p i n g o f the d a t a , which i s a p p a r e n t i n F i g u r e 17. In o r d e r t o e s t i m a t e t h e r e s u l t i n g l a c k o f a c c u r a c y , I re-examined a random sample o f 30 specimens f o r d e n s i t y o f g l a n d u l a r h a i r s and l o n g p i l o s e h a i r s . The d a t a o b t a i n e d was compared s t a t i s t i c a l l y t o d a t a r e c o r d e d e a r l i e r f r o m t h e same spec i m e n s . The c o r r e l a t i o n c o e f f i c i e n t , r , was 0.877 f o r g l a n d u l a r h a i r s and 0.940 f o r l o n g p i l o s e h a i r s . Both t h e s e v a l u e s a r e h i g h l y s i g n i f i c a n t (P « 0.01) and i t i s t h e r e f o r e assumed t h a t t h e measurements p l o t t e d i n F i g u r e 17 a r e - 44 -a c c u r a t e . F i g u r e 18 shows the numbers o f f l o w e r heads p e r i n f l o r e s c e n c e i n t h e H i e r a c i u m t r i s t e - H . g r a c i l e complex. (The number o f i n f l o r e s c e n c e s on a p l a n t i s u s u a l l y one, but sometimes more.) Almost a l l the specimens examined had f l o w e r heads fewer than t e n . P l a n t s grown i n c u l t i v a t i o n f o r c r o s s i n g e x p e r i m e n t s were much l a r g e r , and produced an a v e r a g e o f perhaps 30 f l o w e r heads per p l a n t (most o f t h e s e i n a s i n g l e i n f l o r e s c e n c e ) . Some o f the specimens grown i n c o l d frames o r i n f i e l d p l o t s produced more than 100 heads. The seed from which t h e s e p l a n t s were grown was a l l c o l l e c t e d i n the w i l d , from s m a l l p l a n t s w i t h few f l o w e r heads. C l e a r l y , r e p r o d u c t i v e c a p a c i t y i n t h e s e p l a n t s i s g r e a t l y i n f l u e n c e d by e n v i r o n m e n t . In t h e i r u s u a l a l p i n e o r a r c t i c h a b i t a t s t h e y s u r v i v e under r i g o r o u s growing c o n d i t i o n s . There i s a c o n s i d e r a b l e d i f f e r e n c e between h a b i t a t s o f t h i s t y p e , and a l o w - e l e v a t i o n n u r s e r y p l o t w i t h h i g h e r t e m p e r a t u r e s , a l o n g e r growing s e a s o n , more f e r t i l e s o i l , and an a b s e n c e o f c o m p e t i t i o n . S i n c e t h e phenotype o f H_. t r i s t e and H_. g r a c i l e i s v e r y p l a s t i c w i t h r e s p e c t t o numbers o f f l o w e r heads, any taxonomic d i v i s i o n s based on t h i s c h a r a c t e r s h o u l d be r e g a r d e d w i t h s u s p i c i o n . H i e r a c i u m g r a c i l e v a r . minimum A. N e l s . ( d e s c r i b e d i n 1896) i n c l u d e s a l l p l a n t s w i t h s o l i t a r y heads. F i g u r e 18 shows t h a t the most f r e q u e n t l y e n c o u n t e r e d number o f f l o w e r heads was two. More r e c e n t l y , P o r s i l d (1950) d e s c r i b e d H_. g r a c i l e v a r . yukonense, which d i f f e r s from t y p i c a l H_. g r a c i l e i n the l a r g e r , s t u r d i e r growth o f a l l i t s p a r t s . I have examined s e v e r a l specimens o f t h i s v a r i e t y ( i n c l u d i n g the t y p e ) and I can f i n d no d i f f e r e n c e s from t h e t y p i c a l phase, o t h e r than s i z e . - 45 -F i g u r e 18. Numbers o f f l o w e r heads i n the H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e complex. 24fJr 23t> 22(1 140 130 120| 110 </> 90 +-> c n3 60 s-cu -Q § 50 40 30 •20 i—i i . . i n n n r~i 10 20 30 Number o f f l o w e r heads per p l a n t so - 46 -I t i s p o s s i b l e t h a t t h e s e p l a n t s a r e p o l y p l o i d , but u n t i l t h i s can be shown t h e r e seems t o be no b a s i s f o r r e g a r d i n g them as d i s t i n c t . - 47 -I I I . REPRODUCTIVE BIOLOGY The p a t t e r n s o f v a r i a b i l i t y i n p l a n t s p e c i e s a r e g r e a t l y i n f l u e n c e d by t h e i r methods o f r e p r o d u c t i o n and by t h e i r i n t e r f e r t i l i t y w i t h r e l a t e d s p e c i e s w i t h which t h e y come i n c o n t a c t . In H i e r a c i u m a number o f European s p e c i e s a r e known t o be a p o m i c t i c ( O s t e n f e l d & Rosenberg 1906, Bergman 1935, G u s t a f s s o n 1946-1947, and S k a l i n s k a 1969, among o t h e r s ) . L i t t l e i n v e s t i g a t i o n has been c a r r i e d o u t on North American s p e c i e s , e x c e p t f o r one r e p o r t by A l t o n G u s t a f s o n (1933) on H_. canadense from New E n g l a n d and Quebec. H i s m a t e r i a l was a p o m i c t i c . H i e r a c i u m umbellatum, i t s c l o s e r e l a t i v e , i s d i s c u s s e d i n t h i s c h a p t e r . The e x i s t e n c e o f n a t u r a l l y o c c u r r i n g h y b r i d s i n the hawkweed s p e c i e s o f Europe may be i n f e r r e d from the l a r g e number o f c l o s e l y r e l a t e d m i c r o s p e c i e s ( s e e Zahn 1921-1923). A number o f a r t i f i c i a l c r o s s e s have been a t t e m p t e d ( w i t h v a r i a b l e s u c c e s s ) u s i n g European s p e c i e s (Mendel 1869; O s t e n f e l d 1910, 1912 and 1921; C h r i s t o f f 1942). I n v e s t i g a t i o n s o f h y b r i d i t y i n the New World hawkweeds a r e r e s t r i c t e d t o two p u b l i s h e d r e p o r t s . Anderson & S t e b b i n s (1954) r e p o r t e d h y b r i d i z a t i o n between H_. argutum N u t t . and H_. a l b i f l o r u m i n C a l i f o r n i a , and K r u c k e b e r g (1967) found n a t u r a l h y b r i d s between H_. g r a c i l e and H_. a l b i f l o r u m i n a d i s t u r b e d s u b a l p i n e h a b i t a t i n Washington S t a t e . D u r i n g two summers, I c a r r i e d o u t f i e l d and greenhouse e x p e r i m e n t s on the B r i t i s h Columbia H i e r a c i u m s p e c i e s t o d e t e r m i n e what k i n d o f r e p r o d u c t i o n o c c u r s i n e a c h , and which t a x a ( i f any) a r e i n t e r f e r t i l e . Seed o f most s p e c i e s was c o l l e c t e d i n the w i l d , and sown i n the f a l l o f 1972. S e e d l i n g s were grown i n t h e greenhouse u n t i l e s t a b l i s h e d , then moved o u t s i d e the n e x t - 48 -s p r i n g . These were l a t e r supplemented w i t h mature p l a n t s t r a n s p l a n t e d from the w i l d . The c o l l e c t i o n s i t e s f o r a l l m a t e r i a l o b t a i n e d a r e g i v e n i n T a b l e I I . Voucher specimens f r o m a l l c o l l e c t i o n s are d e p o s i t e d i n t h e U n i v e r s i t y o f B r i t i s h . C o l u m b i a Herbarium. B r e e d i n g System. A p o m i x i s , a c c o r d i n g t o t h e d e f i n i t i o n s o f G u s t a f s s o n (1946) and D a v i s & Heywood (1963 ) , i s o f two t y p e s : v e g e t a t i v e r e p r o d u c t i o n , i n v o l v i n g p r o p a g u l e s o t h e r than s e e d s , and agamospermy, i n which seeds a r e formed by non-sexual p r o c e s s e s . T h e r e a r e a number o f d i f f e r e n t ways i n which agamic p l a n t s may c i r c u m v e n t m e i o s i s . One o f t h e s e (pseudogamy) r e q u i r e s p o l l i n a t i o n f o r t h e endosperm to d e v e l o p , and t h e r e f o r e i s v e r y d i f f i c u l t t o d i s t i n g u i s h from o r d i n a r y s e x u a l r e p r o d u c t i o n e x c e p t by d i r e c t o b s e r v a t i o n o f gametophyte development. In H i e r a c i u m , however, as w e l l as i n t h e r e l a t e d genera C r e p i s , C h o n d r i l l a and Taraxacum, endosperm development i s autonomous and seed s e t i s u n a f f e c t e d by t h e absence o f p o l l e n ( G u s t a f s s o n 1946-1947). The s p e c i e s were t e s t e d f o r a p o m i x i s by e m a s c u l a t i n g f l o w e r heads i n the manner d e s c r i b e d by R a u n k i a e r ( 1 9 0 3 ) , O s t e n f e l d & Rosenberg ( 1 9 0 6 ) , and B a r k e r (1966). Buds a l m o s t r e a d y t o open were c u t t h r o u g h w i t h a s c a l p e l j u s t above the o v a r i e s , removing t h e a n t h e r s , s t i g m a s , and upper p a r t s o f t h e s t y l e s , c o r o l l a s and i n v o l u c r a l b r a c t s . P l a n t s were then p l a c e d i n an i n s e c t -f r e e cage made by s t r e t c h i n g f i n e - m e s h n y l o n n e t t i n g on a wooden frame. T h i s p r e v e n t e d p o s s i b l e p o l l i n a t i o n o f the c u t ends o f t h e s t y l e s , though i t i s l i k e l y t h a t t h i s would n o t o c c u r i n any c a s e s i n c e the c u t s u r f a c e s r a p i d l y become c o v e r e d w i t h l a t e x . P l a n t s which produced v i a b l e seed a f t e r t h i s T a b l e I I . C o l l e c t i o n s i t e s o f t h e p l a n t m a t e r i a l used f o r b r e e d i n g e x p e r i m e n t s . C o l l e c t i o n M a t e r i a l S p e c i e s number c o l l e c t e d l o c a l i t y H_. umbel!atum 92, 140 s e e d Road c l e a r a n c e one m i l e e a s t o f Sunday Summit on the H o p e - P r i n c e t o n Highway. 122 seed Roadside i n d r y c o n i f e r o u s f o r e s t , a l o n g the r o a d t o P a i n t e d Chasm ( l e a v i n g Highway 97 f i f t e e n m i l e s n o r t h o f C l i n t o n ) . 146 l i v e p l a n t Roadside one t o two m i l e s e a s t o f the C h r i s t i n a - K i n n a i r d Summit on Highway 3. 153 l i v e p l a n t Rocky b l u f f a t r o a d s i d e , one m i l e west o f N e l s o n . 155 l i v e p l a n t Dry bank i n Ponderosa Pine and Douglas F i r f o r e s t , on west arm o f Kootenay Lake e i g h t m i l e s e a s t o f N e l s o n . 160 l i v e p l a n t F o r e s t c l e a r i n g near t u f a d e p o s i t , 2.7 m i l e s west o f K a s l o on the r o a d t o New Denver. 163, 165 l i v e p l a n t s G r a v e l l y bank a l o n g r o a d on e a s t s i d e o f Kootenay Lake, 8.8 m i l e s n o r t h o f B o s w e l l . 207 l i v e p l a n t Roadside on Green Mountain Road (west o f P e n t i c t o n ) one m i l e e a s t o f the t u r n o f f t o Mount Apex. 1 A l l c o l l e c t i o n numbers a r e mine e x c e p t RLT 5637, which was c o l l e c t e d by Roy L. T a y l o r . 2A11 m a t e r i a l was c o l l e c t e d i n B r i t i s h Columbia. T a b l e I I . ( c o n t ' d ) C o l l e c t i o n M a t e r i a l S p e c i e s number c o l l e c t e d JH. a l b e r t i n u m 13, 16, 17, seed and l i v e 355, 356 p l a n t s H_. c y n o g l o s s o i d e s 33 seed 145 l i v e p l a n t s H. s c o u l e r i 42, 52, 62 seed JH. a l b i f l o r u m 3 t o 9 seed 151 l i v e p l a n t 154, 157, 159 l i v e p l a n t 161 l i v e p l a n t L o c a l i t y S u b a l p i n e meadows on Morgan M o u n t a i n , on the west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n . ( e l e v . 5000') S u b a l p i n e meadows on Morgan M o u n t a i n , on the west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n . ( e l e v . 4500' t o 5000') Dry open f i e l d w i t h Douglas F i r and Western L a r c h , i n Johnstone Creek Campsite e a s t o f Osoyoos on Highway 3. C l e a r i n g s i n s u b a l p i n e f o r e s t on Morgan Mountain, on the west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n . ( e l e v . 4000' t o 4500') Ponderosa P i n e f o r e s t a l o n g r o a d t o B o t a n i e V a l l e y n o r t h o f L y t t o n . F o r e s t edge a l o n g r o a d c l e a r a n c e , 3 t o 4 m i l e s west o f K i n n a i r d on Highway 3. Dry bank i n Ponderosa P i n e and Douglas F i r f o r e s t , on west arm o f Kootenay Lake e i g h t m i l e s e a s t o f N e l s o n . F o r e s t c l e a r i n g near t u f a d e p o s i t , 2.7 m i l e s west o f K a s l o on the r o a d t o New Denver. T a b l e I I . ( c o n t ' d ) C o l l e c t i o n M a t e r i a l S p e c i e s number c o l l e c t e d H_. a l b i f l o r u m 162 l i v e p l a n t ( c o n t ' d ) H. g r a c i l e 128 s e e d 137 seed RLT 5637 seed 367, 368, 369 l i v e p l a n t s L o c a l i t y Moss-covered r o c k o u t c r o p on west s i d e o f Kootenay Lake, e i g h t m i l e s e a s t o f N e l s o n . A l o n g rtoadside i n . d i s t u r b e d s o i l , on Mount Apex west o f P e n t i c t o n . A l p i n e meadow on Mount Seymour, N o r t h Vancouver. A l p i n e meadow on the I l g a c h u z Mountains n o r t h o f Anahim Lake. Dry a l p i n e meadow ( e l e v . 6500') on C o r n w a l l Lookout west o f A s h c r o f t . - 52 -t r e a t m e n t were c o n s i d e r e d a p o m i c t i c ; t h o s e which d i d not were assumed t o be a m p h i m i c t i c . The p r o c e d u r e i s somewhat d r a s t i c , and c o u l d l e a d t o a b o r t i o n o f t h e seed due t o shock. However, i t has been used s u c c e s s f u l l y on A r n i c a ( B a r k e r 1966), and i n the p r e s e n t s t u d y i t had no a d v e r s e e f f e c t s on a t l e a s t one o f the s p e c i e s . S e x u a l l y r e p r o d u c i n g s p e c i e s were f u r t h e r i d e n t i f i e d as autogamous ( s e l f - f e r t i l i z i n g ) o r exogamous ( o u t c r o s s i n g ) a c c o r d i n g t o t h e i r a b i l i t y t o s e t v i a b l e seed i n the absence o f o u t s i d e p o l l i n a t i n g a g e n t s . D u r i n g development, t h e s t y l e i n a H i e r a c i u m f l o w e r l i e s i n s i d e t he tube formed by the c o a l e s c e n t a n t h e r s . As t h e f l o w e r opens, t h e s t y l e e l o n g a t e s and the sti g m a i s pushed o u t . A l t h o u g h t h e s t i g m a t i c s u r f a c e s a r e f o l d e d t o g e t h e r d u r i n g t h i s p r o c e s s , t h e y may p i c k up p o l l e n as t h e y push p a s t t h e a n t h e r s . P o l l e n was o b s e r v e d s e v e r a l t i m e s on the s t i g m a s o f newly-opened f l o w e r s which had n o t been d i s t u r b e d by p o l l i n a t o r s . For the purposes o f t h e s e e x p e r i m e n t s i t was assumed t h a t s e l f - p o l l i n a t i o n d i d not o c c u r n a t u r a l l y , and u s u a l l y the f l o w e r s were s e l f - p o l l i n a t e d a r t i f i c i a l l y by r u b b i n g t o g e t h e r a d j a c e n t f l o w e r heads on the same p l a n t . However, f l o w e r heads n o t t r e a t e d i n t h i s manner pro d u c e d about the same p r o p o r t i o n o f f e r t i l e seed as t h o s e t h a t were. Lack o f seed s e t under such c o n d i t i o n s would seem t o i n d i c a t e the e x i s t e n c e o f a g e n e t i c s t e r i l i t y b a r r i e r r a t h e r than f a i l u r e o f p o l 1 i n a t i o n . Seeds were g e r m i n a t e d on wet f i l t e r paper i n p e t r i d i s h e s . I n i t i a l t e s t s were done on H_. umbellatum, H_. a l b i f l o r u m and H_. g r a c i l e t o d e t e r m i n e the b e s t c o n d i t i o n s f o r g e r m i n a t i o n . No s i g n i f i c a n t d i f f e r e n c e s were found - 53 -between l i g h t and d a r k c o n d i t i o n s , between t h e p r e s e n c e o r absence o f f u n g i c i d e , o r between s o i l and f i l t e r paper s u b s t r a t e s ( p a i r e d t - t e s t s , w i t h a = 0.05). However, t h e s e t e s t s r e v e a l e d s p e c i e s d i f f e r e n c e s i n g e r m i n a t i n g t i m e . Seeds o f H i e r a c i u m g r a c i l e g e r m i n a t e d r a p i d l y and a l l a t once ( w i t h i n t e n days) and t h o s e o f umbellatum more s l o w l y , o v e r two o r t h r e e weeks. H i e r a c i u m a l b i f l o r u m seeds showed no a c t i v i t y i n t h e f i r s t two weeks, f o l l o w e d by g r a d u a l g e r m i n a t i o n o v e r s i x weeks o r l o n g e r . These a r e q u i t e marked d i f f e r e n c e s , and are p r o b a b l y r e l a t e d t o d i f f e r e n c e s i n h a b i t a t p r e f e r e n c e . Seed g e r m i n a t i o n i s d i s c u s s e d f u r t h e r i n C h a p t e r VI. The r e s u l t s o f the e x p e r i m e n t s t o d e t e r m i n e b r e e d i n g s y s t e m a r e g i v e n i n T a b l e I I I , and T a b l e IV shows s t a t i s t i c a l c o mparisons o f t h e s e r e s u l t s . I t i s i n t e r e s t i n g t h a t H. g r a c i l e and H_. a l b i f l o r u m , both o f which a r e s e l f - p o l l i n a t i n g s p e c i e s , have the s m a l l e s t f l o w e r heads o f the s p e c i e s s t u d i e d . The t h r e e s p e c i e s o f the JH. s c o u l e r i complex a r e a l l o u t c r o s s i n g , and p r o d u c e ' t h e most abundant p o l l e n . H i e r a c i u m umbellatum i s c l e a r l y a p o m i c t i c , and seeds from the e m a s c u l a t e d f l o w e r heads have a g e r m i n a t i o n r a t e o n l y s l i g h t l y l e s s than t h a t o f u n d i s t u r b e d s e e d s . No e f f o r t was made to d e t e r m i n e t h e r e l a t i v e e x t e n t o f a p o m i x i s and s e x u a l r e p r o d u c t i o n i n t h i s s p e c i e s , though i t seems l i k e l y t h a t most o f t h e seed s e t i s the r e s u l t o f a p o m i x i s . M a r s h a l l & Brown (1974) have d e s c r i b e d a method f o r e s t i m a t i n g the e x t e n t o f a p o m i x i s i n p l a n t p o p u l a t i o n s , but i t r e q u i r e s some g e n e t i c knowledge o f the s p e c i e s b e i n g s t u d i e d . A l l the o t h e r s p e c i e s i n c l u d e d i n the p r e s e n t s t u d y y i e l d e d a h i g h p r o p o r t i o n o f a b o r t e d seed ( s h r u n k e n , c o l l a p s e d and p a l e i n c o l o u r ) from e m a s c u l a t e d heads. The v e r y few seeds T a b l e I I I . R e s u l t s o f e x p e r i m e n t s t o d e t e r m i n e b r e e d i n g system. S p e c i e s F l owers c r o s s -• p o l 1 i n a t e d Flowers s e l f - p o l l i n a t e d Flowers u n p o l l i n a t e d Number o f seeds t e s t e d 2 P e r c e n t Per c e n t good germina-seed t i o n Number o f seeds t e s t e d Per c e n t good seed Per c e n t germina-t i o n Number o f seeds t e s t e d Per c e n t good seed Per c e n t germina-t i o n H. umbellatum 600 90.0 54.4 600 91.0 59.4 550 72.8 48.1 H- a l b e r t i n u m 680 32.1 21.6 1500 1.5 0.9 135 0 0 JH. c y n o g l o s s o i d e s 800 31.2 24.0 1500 1.3 0.9 400 0.5 0.3 H- s c o u l e r i • 1000 47.5 35.7 3000 2.5 1.0 300 0 0 H. a l b i f l o r u m 1200 78.0 52.3 1200 78.8 49.8 240 0 0 g r a c i l e 600 83.1 81.3 600 78.3 75.6 2600 1.0 0.9 % g r a c i l e 1200 87.4 70.6 1200 82.1 76.9 1125 1.3 1.1 *No JH. canadense was e n c o u n t e r e d d u r i n g f i e l d e x p e d i t i o n s , a l t h o u g h c o n s i d e r a b l e e f f o r t s were made t o l o c a t e m a t e r i a l o f t h i s s p e c i e s . A l l o f t h e p l a n t s c o l l e c t e d proved t o be JH_. umbel latum. 2Good seed was d a r k brown, plump and 2 t o 3 mm l o n g . Only t h i s seed g e r m i n a t e d . M a t e r i a l from t h e I l g a c h u z M o u n t a i n s . These p l a n t s showed d e f i n i t e t e n d e n c i e s toward JH. t r i s t e . ( L i v e m a t e r i a l o f t y p i c a l H_. t r i s t e f o r t h e s e e x p e r i m e n t s was not o b t a i n e d . ) "*Material from Mount Apex and Mount Seymour. - 55 -T a b l e IV. S t a t i s t i c a l c o m p a r i s o n s o f g e r m i n a t i o n r a t e s . S p e c i e s Groups compared R e s u l t s ri - u mbellatum seeds f r o m o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads seeds from o p e n - p o l l i n a t e d and u n p o l l i n a t e d heads d i f f e r e n c e n o t s i g n i f i c a n t ( X 2 = 3.06, P > 0.1) d i f f e r e n c e n o t s i g n i f i c a n t ( X 2 = 4.52, P > 0.1) l l . a l b e r t i n u m seeds f r o m o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads d i f f e r e n c e s i g n i f i c a n t ( X 2 = 293, P « 0.001) H. c y n o g l o s s o i d e s seeds f r o m o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads d i f f e r e n c e s i g n i f i c a n t ( X 2 = 341, P « 0.001) H. s c o u l e r i seeds from o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads d i f f e r e n c e s i g n i f i c a n t ( x 2 = 954, P « 0.001) H. a l b i f l o r u m seeds from o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads seeds f r o m o p e n - p o l l i n a t e d and u n p o l l i n a t e d heads d i f f e r e n c e n o t s i g n i f i c a n t ( X 2 = 1.5, P > 0.1) d i f f e r e n c e s i g n i f i c a n t ( x 2 = 224, P « 0.001) H. g r a c i l e ( m a t e r i a l from I l g a c h u z Mts.) seeds f r o m o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads seeds from o p e n - p o l l i n a t e d and u n p o l l i n a t e d heads d i f f e r e n c e n o t s i g n i f i c a n t ( X 2 = 5.71, P > 0.05) d i f f e r e n c e s i g n i f i c a n t ( X 2 = 2346, P « 0.001) H. g r a c i l e ( m a t e r i a l f r o m Mt.' Apex and Mt. Seymour) seeds from o p e n - p o l l i n a t e d and s e l f - p o l l i n a t e d heads seeds f r o m o p e n - p o l l i n a t e d and u n p o l l i n a t e d heads d i f f e r e n c e s i g n i f i c a n t ( X 2 = 12.4, P < 0.005) d i f f e r e n c e s i g n i f i c a n t ( X 2 = 1207, P « 0.001) Note: In a d d i t i o n t o t h e above, a c o m p a r i s o n was made among v a r i o u s groups o f t h e per c e n t g e r m i n a t i o n o f se e d i n c r o s s - p o l l i n a t e d f l o w e r heads. (a) s p e c i e s o f t h e H_. s c o u l e r i complex - a s i m u l t a n e o u s c o m p a r i s o n o f t h e t h r e e s p e c i e s t o g e t h e r shows t h a t t h e y a r e s i g n i f i c a n t l y d i f f e r e n t (P < 0.001), but H.. a l b e r t i n u m and H. c y n o g l o s s o i d e s a r e n o t s i g n i f i c a n t l y d i f f e r e n t f r o m one a n o t h e r (x ~ 1-25, P > 0.5). (b) H. g r a c i l e - the two p o p u l a t i o n s a r e s i g n i f i c a n t l y d i f f e r e n t Tx2 = 2 4 . 1 , P < 0.001). - 56 -t h a t were pr o d u c e d under t h e s e c o n d i t i o n s may have r e s u l t e d from c a r e l e s s n e s s i n t e c h n i q u e , o r perhaps from s e l f - p o l l i n a t i o n t h a t o c c u r r e d b e f o r e t he a n t h e r s were removed. The s p e c i e s o f the H i e r a c i u m s c o u l e r i complex a l s o p r o d u c e d a few v i a b l e seeds when s e l f - p o l l i n a t e d . The g r e a t l y r e d u c e d p r o p o r t i o n o f such seed i n d i c a t e s t h a t t h e p l a n t s a r e o u t c r o s s e r s , but even s e l f - i n c o m p a t i b l e s p e c i e s may be c a p a b l e o f a sm a l l d e g r e e o f s e l f -f e r t i l i z a t i o n . None o f the s p e c i e s e x c e p t H_. g r a c i l e had v e r y h i g h seed s e t under c u l t i v a t i o n , even when ample p o l l e n was a v a i l a b l e . T h i s may be due t o s t r e s s imposed by t h e growing c o n d i t i o n s . In hot weather, a l l t h e p l a n t s used were s u b j e c t t o f a i r l y h i g h t e m p e r a t u r e s and t o some degree o f d e s s i c a t i o n . H i e r a c i u m a l b e r t i n u m , H_. c y n o g l o s s o i d e s and HL s c o u l e r i were p a r t i c u l a r l y s u s c e p t i b l e , and sometimes i n t h e s e s p e c i e s t h e i n f l o r e s c e n c e d i e d back p r e m a t u r e l y . H y b r i d i z a t i o n E x p e r i m e n t s . To d e t e r m i n e which o f the hawkweeds i n c l u d e d i n t h i s s t u d y were c a p a b l e o f i n t e r b r e e d i n g , r e c i p r o c a l c r o s s e s were attempted between a l l p o s s i b l e p a i r s o f s p e c i e s . For the purposes o f t h i s e x p e r i m e n t , H_. umbellatum was t r e a t e d as a f a c u l t a t i v e a p o m i c t and was assumed t o be c a p a b l e o f a t l e a s t o c c a s i o n a l s e x u a l r e p r o d u c t i o n . The c o n s i d e r a b l e a r r a y o f m i c r o s p e c i e s r e l a t e d t o t h e European H_. umbellatum (see Zahn 1921-1923) has p r o b a b l y r e s u l t e d from o c c a s i o n a l h y b r i d i z a t i o n between n o r m a l l y a p o m i c t i c l i n e s . H i e r a c i u m umbellatum i t s e l f i s p r e d o m i n a n t l y d i p l o i d and a m p h i m i c t i c i n Europe ( O s t e n f e l d & Rosenberg 1906, G u s t a f s s o n 1946-1947). O s t e n f e l d (1921) - 57 -f a i l e d i n h i s at t e m p t s t o c r o s s H i e r a c i u m umbellatum w i t h r e l a t e d s p e c i e s . However, Mendel (1869), i n h i s e a r l y work on i n h e r i t a n c e , was a p p a r e n t l y s u c c e s s f u l i n o b t a i n i n g h y b r i d s i n v o l v i n g H_. umbellatum; one o f t h e s e was a c r o s s w i t h H_. vu l g a t u m F r . and the o t h e r was o f i n c o m p l e t e l y known p a r e n t a g e . C r o s s e s between a p o m i c t i c l i n e s may have l e d t o p o l y p l o i d y i n some H i e r a c i u m s p e c i e s , due t o t h e f o r m a t i o n o f unreduced gametes ( S k a l i n s k a 1970 and 1973), though t h i s has not been i n v e s t i g a t e d i n the subgenus E u h i e r a c i u m . H y b r i d i z a t i o n e x p e r i m e n t s f o r t h i s s t u d y were done i n t h e summer o f 1973. A l l the s p e c i e s o v e r l a p p e d i n f l o w e r i n g t i m e . Flower heads on d i f f e r e n t p l a n t s were c r o s s - p o l l i n a t e d by b r u s h i n g them a g a i n s t one a n o t h e r , and were t h e n l a b e l l e d w i t h c o l o u r - c o d e d t a g s i n d i c a t i n g t h e s p e c i e s o f the p o l l e n - p a r e n t . The p l a n t s used were kept i n an i n s e c t - f r e e cage d u r i n g t he f l o w e r i n g p e r i o d . Seeds were c o l l e c t e d a t m a t u r i t y and s t o r e d under r e f r i g e r a t i o n . When the above t e c h n i q u e i s used on s e l f - c o m p a t i b l e s p e c i e s , a few h y b r i d s may be produced but most o f t h e o f f s p r i n g a r e t h e r e s u l t o f s e l f -p o l l i n a t i o n and re s e m b l e t h e female p a r e n t . I n i t i a l l y , an a t t e m p t was made to overcome t h i s problem by removing t h e a n t h e r s b e f o r e a n t h e s i s . T h i s was abandoned f o r two r e a s o n s : (a) t he i n d i v i d u a l f l o w e r s were v e r y s m a l l ( e s p e c i a l l y i n JH. g r a c i l e ) and were d i f f i c u l t t o m a n i p u l a t e w i t h o u t damage. (b) when at t e m p t s a t e m a s c u l a t i o n were s u c c e s s f u l , t he a n t h e r s u s u a l l y remained c o n n a t e and s l i d o f f o v e r t he end o f the s t i g m a , s c a t t e r i n g p o l l e n as t h e y d i d so. - 58 -H y b r i d s were t h e r e f o r e o b t a i n e d by r a i s i n g a l l s e e d l i n g s t o m a t u r i t y , a t which time m o r p h o l o g i c a l d i f f e r e n c e s became a p p a r e n t . Seed from the c r o s s e s was sown i n the f a l l and the s e e d l i n g s o v e r w i n t e r e d i n t h e greenhouse t o a c c e l e r a t e development. In the s p r i n g the p l a n t s were s e t o u t i n a f i e l d p l o t . H y b r i d i n d i v i d u a l s were i d e n t i f i e d by the p r e s e n c e o f c o m b i n a t i o n s o f m o r p h o l o g i c a l f e a t u r e s from d i f f e r e n t p a r e n t s p e c i e s . P r e s s e d specimens o f a l l h y b r i d s o b t a i n e d and o f i n d i v i d u a l s from the p a r e n t p o p u l a t i o n s a r e i n t he U n i v e r s i t y o f B r i t i s h Columbia Herbarium. The f o l l o w i n g c r o s s e s attempted w i t h s p e c i e s o f t h e H i e r a c i u m s c o u l e r i group y i e l d e d l i t t l e o r no seed due t o e a r l y w i t h e r i n g o f the stem: JH. a l b e r t i n u m X H_. g r a c i l e JH. g r a c i l e X JH. a l b e r t i n u m H,. c y n o g l o s s o i d e s X JH. a l b i f l o r u m JH. s c o u l e r i X H. g r a c i l e E f f o r t s t o a c h i e v e c r o s s e s i n v o l v i n g JH. umbellatum as t h e female p a r e n t r e s u l t e d i n l a r g e numbers o f o f f s p r i n g (two to t h r e e hundred) but no h y b r i d s . Nor was the p o l l e n o f t h i s hawkweed e f f e c t i v e w i t h the o t h e r s p e c i e s . The p o l l e n produced may n o t have been v i a b l e , as i s t r u e o f many a p o m i c t i c s p e c i e s . On the o t h e r hand, H_. umbellatum i s much more d i s t a n t l y r e l a t e d to the o t h e r hawkweeds than t h e y a r e to\; each o t h e r , and i n a d d i t i o n i t d i f f e r s from them i n p l o i d y l e v e l (see C h a p t e r I V ) ; t h e s e f a c t o r s would be s u f f i c i e n t t o p r e v e n t c r o s s i n g even i f JH. umbellatum was f u l l y f e r t i l e . R e c i p r o c a l c r o s s e s were attempted w i t h a l l p a i r s o f s p e c i e s , but i n most cases (owing t o poor g e r m i n a t i o n and h i g h s e e d l i n g m o r t a l i t y i n some o f the s p e c i e s ) o n l y one o f the two p o s s i b l e c o m b i n a t i o n s was o b t a i n e d . In - 59 -t h o s e i n s t a n c e s where both c r o s s e s s u r v i v e d , t h e y were m o r p h o l o g i c a l l y v e r y s i m i l a r . The c r o s s e s t h a t y i e l d e d r e c o g n i z a b l e h y b r i d s a r e d e s c r i b e d i n T a b l e V. An a r t i f i c i a l h y b r i d between H i e r a c i u m c y n o g l o s s o i d e s and H_. g r a c i l e , t o g e t h e r w i t h i t s p a r e n t s p e c i e s , i s i l l u s t r a t e d i n P l a t e 2. The t h r e e s p e c i e s o f the IH. s c o u l e r i complex appear t o be c o m p l e t e l y i n t e r f e r t i l e . Many d i f f e r e n t d e g r e e s o f h a i r i n e s s can be o b s e r v e d wherever two o r more o f the t a x a a r e growing t o g e t h e r . A l o n g the west s i d e o f B o t a n i e V a l l e y near L y t t o n , a l l t h r e e s p e c i e s can be found on the same h i l l s i d e w i t h i n a few metres o f one a n o t h e r . ATI the p l a n t s , whether o f i n t e r m e d i a t e a ppearance o r n o t , s e t f e r t i l e seed and appear t o have v i a b l e p o l l e n . The same c o n d i t i o n s o f i n t e r f e r t i l i t y appear t o h o l d f o r H_. t r i s t e and H_. g r a c i 1e. The specimens o f H_. g r a c i l e t h a t were grown under c u l t i v a t i o n (see T a b l e I I ) were th e m s e l v e s f e r t i l e , c r o s s e d r e a d i l y w i t h one a n o t h e r and y i e l d e d a l l f e r t i l e o f f s p r i n g . However, no t y p i c a l examples o f H_. t r i s t e were o b t a i n e d , so the c r o s s a b i l i t y o f the two m o r p h o l o g i c a l extremes o f t h i s complex remains t o be t e s t e d . The h y b r i d s between s e c t i o n s a r e o f g r e a t e r i n t e r e s t . In the e x p e r i m e n t s done h e r e , i n which most o f t h e i s o l a t i n g f a c t o r s t h a t o p e r a t e i n t h e w i l d were e l i m i n a t e d , s p e c i e s from d i f f e r e n t s e c t i o n s o f the subgenus S t e n o t h e c a a l l h y b r i d i z e d r e a d i l y w i t h one a n o t h e r . However, h y b r i d s a r e a l s o known from - 60 -T a b l e V. M o r p h o l o g i c a l f e a t u r e s o f the h y b r i d s o b t a i n e d f r o m c r o s s i n g e x p e r i m e n t s . C r o s s 1 D e s c r i p t i o n H. c y n o g l o s s o i d e s X H_. a l b e r t i n u m H_. s c o u l e r i X HL c y n o g l o s s o i d e s H. s c o u l e r i X H. a l b i f l o r u m H. a l b i f l o r u m X H. a l b e r t i n u m A l l l e a v e s d e n s e l y s e t o s e , i n v o l u c r e s p a r s e l y s e t o s e . Leaves s p a r s e l y s e t o s e (uppermost c a u l i n e l e a v e s sometimes g l a b r o u s ) , i n v o l u c r e l a c k i n g s e t o s e h a i r s . Leaves v e r y s p a r s e l y s e t o s e (upper c a u l i n e l e a v e s g l a b r o u s ) ; i n f l o r e s c e n c e much more branched and open than i n H_. s c o u l e r i ; i n v o l u c r e w i t h a few y e l l o w g l a n d u l a r h a i r s and o c c a s i o n a l s t e l l a t e h a i r s , s i z e o f f l o w e r heads i n t e r m e d i a t e between t h a t o f p a r e n t s : f l o w e r s p a l e y e l l o w 2 . P l a n t a p p r o x i m a t e l y 7 dm t a l l , l a r g e and d e n s e l y s e t o s e , s l i g h t l y g l a u c o u s ; stem g l a b r o u s above. I n f l o r e s c e n c e much more branched and open than i n H_. a l b e r t i n u m ; i n v o l u c r e w i t h l o n g w h i t e h a i r s , s p a r s e l y t o m o d e r a t e l y s t e l l a t e and w i t h y e l l o w , b l a c k - s t a l k e d g l a n d s ; f l o w e r s p a l e y e l l o w . P l a n t h e i g h t 5 t o 8 dm; lower l e a v e s d e n s e l y s e t o s e , uppermost c a u l i n e l e a v e s g l a b r o u s ; f l o w e r heads o f t e n numerous; l o n g h a i r s on i n v o l u c r e few t o a l m o s t none. O t h e r w i s e l i k e H_. a l b i f l o r u m X H_. a l b e r t i n u m . Leaves s p a r s e l y s e t o s e , s l i g h t l y g l a u c o u s . ( P l a n t s d i e d b e f o r e r e a c h i n g m a t u r i t y . ) P l a n t about 3 dm t a l l ; l e a v e s m o s t l y b a s a l , o b l a n c e o l a t e t o s p a t u l a t e , rounded ( e x c e p t c a u l i n e l e a v e s a c u t e ) , s t e l l a t e and s p a r s e l y l o n g - h a i r y . Stem s t e l l a t e ; 1ln a l l c a s e s t he female p a r e n t i s l i s t e d f i r s t . 28B on Royal H o r t i c u l t u r a l S o c i e t y c o l o u r c h a r t ; H_. s c o u l e r i i s 6B. H_. a l b i f l o r u m X H_. c y n o g l o s s o i d e s H. a l b i f l o r u m X H. s c o u l e r i H_. g r a c i l e X H_. c y n o g l o s s o i d e s T a b l e V. ( c o n t ' d ) Cross H_. g r a c i l e X H_. c y n o g l o s s o i d e s ( c o n t ' d ) H_. g r a c i l e X H. s c o u l e r i H. g r a c i l e X H. a l b i f l o r u m D e s c r i p t i o n f l o w e r heads and i n v o l u c r e i n t e r m e d i a t e i n s i z e between t h o s e o f the p a r e n t s p e c i e s ; i n v o l u c r e d e n s e l y s t e l l a t e , g l a n d u l a r ( w i t h both y e l l o w and b l a c k g l a n d s ) and w i t h l o n g w h i t e h a i r s . Leaves s t e l l a t e , c i l i a t e at. margins o n l y ; i n v o l u c r e d e n s e l y s t e l l a t e , . w i t h some s h o r t b l a c k h a i r s and some g l a n d u l a r h a i r s ( t a l l b l a c k , s h o r t y e l l o w , and i n t e r m e d i a t e ) . O t h e r w i s e l i k e H_. g r a c i l e X H_. c y n o g l o s s o i d e s . P l a n t s up t o 8 dm t a l l ; l e a v e s l i g h t g r e e n , o b l a n c e o l a t e , a c u t e , s l i g h t l y s e t o s e , f i n e l y d e n t i c u l a t e . Stem l e a v e s r e d u c e d . Stem r e d d i s h , s e t o s e a t base, g l a b r o u s f u r t h e r up and d e n s e l y s t e l l a t e i n the i n f l o r e s c e n c e ; i n v o l u c r e s t e l l a t e , w i t h s m a l l y e l l o w g l a n d u l a r h a i r s and a few l o n g h a i r s ; f l o w e r s p a l e y e l l o w 3 and i n t e r m e d i a t e i n s i z e between t h o s e o f the p a r e n t s . 36A on Royal H o r t i c u l t u r a l S o c i e t y c o l o u r c h a r t ; H. g r a c i l e i s : 6 B . P l a t e 2. P r e s s e d specimens o f H i e r a c i u m c y n o g l o s s o i d e s ( l e f t ) , H. g r a c i l e ( r i g h t ) and the a r t i f i c i a l l y p r o d u c e d f i r s t - g e n e r a t i o n h y b r i d between them ( c e n t r e ) . - 63 -n a t u r e . H i e r a c i u m a l b i f l o r u m , though commonly found a l o n g r o a d s i d e s and i n o t h e r d i s t u r b e d s i t e s , may a l s o c o - o c c u r w i t h members o f the H_. s c o u l e r i complex. I t forms n a t u r a l h y b r i d s w i t h JH_. c y n o g l o s s o i d e s a l o n g the L y t t o n -B o t a n i e r o a d and on n e a r b y h i l l s i d e s . Some o f t h e s e h y b r i d s ( e . g . , t h e specimen i l l u s t r a t e d i n P l a t e 3) have v e r y p a l e y e l l o w c o r o l l a s , from which i t i s e v i d e n t t h a t t h e y a r e t h e r e s u l t o f b a c k c r o s s i n g t o H_. a l b i f l o r u m . They a r e s t i l l c l e a r l y d i s t i n g u i s h a b l e as h y b r i d s , however, by t h e s i z e o f the f l o w e r heads and by t h e s p a r s e l y s t e l l a t e f o l i a g e . F i r s t - g e n e r a t i o n a r t i f i c i a l h y b r i d s between H_. a l b i f l o r u m and t h e H_. s c o u l e r i complex were g e n e r a l l y found t o v e r y c l o s e l y resemble t h e l a t t e r group. The h y b r i d between H_. a l b i f l o r u m and JH_. g r a c i l e i s e a s i l y d i s t i n g u i s h e d from i t s two q u i t e d i f f e r e n t p a r e n t s p e c i e s . The n a t u r a l h a b i t a t s o f t h e s e two s p e c i e s ( e a r l y s u c c e s s i o n a l s i t e s a t low t o m i d d l e e l e v a t i o n s , and a l p i n e meadows a t h i g h e l e v a t i o n s , r e s p e c t i v e l y ) do not commonly o v e r l a p . However, a n a t u r a l h y b r i d was c o l l e c t e d d u r i n g t h e c o u r s e o f t h i s s t u d y , i n d i s t u r b e d s o i l a l o n g a r o a d s i d e n o r t h o f S t e w a r t , B r i t i s h Columbia. A t t h i s l a t i t u d e , h a b i t a t s i n which JH_. g r a c i l e i s f o u n d may o c c u r a t q u i t e low e l e v a t i o n s . The h y b r i d p l a n t s were up t o seven dm i n h e i g h t , w i t h b l a c k g l a n d u l a r - h i r s u t e i n v o l u c r e s and l o n g s e t o s e h a i r s on the f o l i a g e . One o f the specimens found i s i l l u s t r a t e d i n P l a t e 4. N a t u r a l h y b r i d s between JH. a l b i f l o r u m and H_. g r a c i l e have a l s o been r e p o r t e d by K r u c k e b e r g (1967) from an o l d burn a t 5000' e l e v a t i o n i n t h e Olympic Mountains. In t h i s c a s e , the d i s t u r b a n c e c a u s e d by the f i r e p e r m i t t e d t h e e s t a b l i s h m e n t o f H_. a l b i f l o r u m . In both o f t h e s e i n s t a n c e s t h e h y b r i d s were found growing i n the p r e s e n c e o f the two p a r e n t s p e c i e s . The h y b r i d s i n each case a r e v e r y s i m i l a r i n P l a t e 3. Flower heads o f H i e r a c i u m s c o u l e r i ( a t l e f t , X 2 . 2 ) , H. a l b i f l o r u m ( a t r i g h t , X 1 . 6 ) , and a n a t u r a l h y b r i d between them ( c e n t r e , X 1.4). The h y b r i d has f l o w e r heads i n t e r m e d i a t e i n c o l o u r and s i z e between t h o s e o f t h e two s p e c i e s . I t i s p r o b a b l y a s e c o n d - g e n e r a t i o n b a c k c r o s s t o H. a l b i f l o r u m , s i n c e t h e f i r s t - g e n e r a t i o n h y b r i d u s u a l l y i s much more s i m i l a r t o t h e y e l l o w - f l o w e r e d p a r e n t . - 65 -P l a t e 4. A n a t u r a l h y b r i d between H i e r a c i u m a l b i f l o r u m and H. g r a c i l e , found a t the r o a d s i d e a l o n g t h e S t e w a r t - C a s s i a r Road i n n o r t h e r n B r i t i s h C olumbia. The p l a n t i s about seven dm h i g h . - 66 -morphology t o the a r t i f i c i a l l y g e n e r a t e d p l a n t s d e s c r i b e d i n T a b l e V. No n a t u r a l h y b r i d s between H i e r a c i u m g r a c i l e and t h e s p e c i e s o f t h e JH. s c o u l e r i complex have been c o l l e c t e d . D u r i n g my f i e l d work I found them growing t o g e t h e r o n l y once (H_. g r a c i l e and H_. c y n o g l o s s o i d e s , on a s u b a l p i n e h i l l s i d e a t 5500' e l e v a t i o n i n Manning P a r k ) . The f i r s t - m e n t i o n e d s p e c i e s had e s s e n t i a l l y f i n i s h e d f l o w e r i n g and the second had not y e t r e a c h e d i t s peak, so i t seems r e a s o n a b l e t o h y p o t h e s i z e t h a t where t h e s e s p e c i e s c o - o c c u r t h e y a r e p r o b a b l y i s o l a t e d by d i f f e r e n c e s i n f l o w e r i n g t i m e . F u r t h e r s t u d y o f the h y b r i d s produced d u r i n g t h i s s t u d y would be o f c o n s i d e r a b l e i n t e r e s t , and might y i e l d i n f o r m a t i o n on the g e n e t i c s o f some o f t h e s p e c i e s d i f f e r e n c e s . O n l y t h e F j g e n e r a t i o n was examined h e r e , and most o f t h e h y b r i d p l a n t s were c o l l e c t e d as v o u c h e r specimens w h i l e s t i l l i n f l o w e r , so no i n f o r m a t i o n on t h e i r seed s e t was o b t a i n e d . However, a s i n g l e h y b r i d between H^ . a l b i f l o r u m and H_. c y n o g l o s s o i d e s was p e r m i t t e d t o go t o s e e d , and i t p r o v e d t o be s e l f - i n c o m p a t i b l e . P o l l e n V i a b i l i t y . P o l l e n s t a i n a b i l i t y , a r e a s o n a b l y good i n d i c a t o r o f p l a n t f e r t i l i t y , was measured f o r each o f the s p e c i e s and h y b r i d s f o r which l i v e m a t e r i a l was a v a i l a b l e . P o l l e n g r a i n s from r e c e n t l y opened f l o w e r s were d u s t e d onto m i c r o s c o p e s l i d e s and s t a i n e d w i t h c o t t o n b l u e i n l a c t o p h e n o l . P o l l e n g r a i n s w i t h l i v i n g c y t o p l a s m s t a i n e d dark b l u e ; o t h e r s s t a i n e d v e r y l i g h t b l u e . The r e s u l t s a r e g i v e n i n T a b l e VI. - 67 -T a b l e VI. P o l l e n v i a b i l i t y . Number o f Per c e n t S p e c i e s o r h y b r i d t e s t e d g r a i n s c o u n t e d s t a i n a b l e p o l l e n S p e c i e s : H_. umbellatum 1000 8.6 H_. a l b e r t i n u m " 500 90.4 H_. c y n o g l o s s o i d e s 1000 94.5 H_. s c o u l e r i 500 97.4 H. a l b i f l o r u m 500 94.8 H. g r a c i l e 1 500 91.5 H y b r i d s 2 : H.. s c o u l e r i X JH. a l b i f l o r u m 500 88.7 H_. a l b i f l o r u m X H. c y n o g l o s s o i d e s 880 58.7 H. a l b i f l o r u m X H_. a l b e r t i n u m 500 54.4 H_. g r a c i l e X H. c y n o g l o s s o i d e s 500 22.6 H. g r a c i l e X H. s c o u l e r i 500 17,0 H. g r a c i l e X H. a l b i f l o r u m 1000 23.4 H. a l b e r t i n u m X H. a l b i f l o r u m 3 500 67.4 ( n a t u r a l h y b r i d l P o l l e n from two p o p u l a t i o n s o f H_. g r a c i l e (from Mount Apex and Mount Seymour) was combined f o r t h i s c o u n t . 2 F o r t he h y b r i d specimens, t he f e m a l e p a r e n t i s l i s t e d f i r s t i n each c a s e . 3Grown from seed c o l l e c t e d from a p l a n t o f H_. a l b e r t i n u m i n B o t a n i e V a l l e y . - 68 -P o l l e n v i a b i l i t y i n H i e r a c i u m umbellatum proved to be v e r y low. T h i s may be r e l a t e d t o d e v e l o p m e n t a l a b n o r m a l i t i e s a s s o c i a t e d w i t h a p o m i x i s , but i s a l s o due a t l e a s t p a r t l y t o t h e d i s r u p t i o n o f m e i o s i s caused by p o l y p l o i d y ( s e e C h a p t e r I V ) . A l l t h e o t h e r hawkweed s p e c i e s t h a t were t e s t e d had h i g h l y f e r t i l e p o l l e n . The h y b r i d s between s p e c i e s o f d i f f e r e n t s e c t i o n s d i s p l a y e d somewhat low e r e d p o l l e n v i a b i l i t y . In h y b r i d s between H. a l b i f l o r u m and t h e s p e c i e s o f t h e H_. s c o u l e r i complex, the d e c r e a s e was n o t g r e a t , and one o f the i n d i v i d u a l s examined approached i t s p a r e n t s i n v i a b i l i t y o f p o l l e n . I t i s c l e a r t h a t H_. a l b i f l o r u m and t h e JH. s c o u l e r i complex a r e c l o s e l y r e l a t e d . H y b r i d s i n v o l v i n g H_. g r a c i l e , however, were c o n s i d e r a b l y l e s s f e r t i l e . T h i s i s r e a s o n a b l e i n view o f t h e more c o n s p i c u o u s m o r p h o l o g i c a l d i f f e r e n c e s t h a t d i s t i n g u i s h t h i s s p e c i e s . - 69 -IV. CYTOGENETICS Study o f a p l a n t ' s chromosomes may be o f c o n s i d e r a b l e v a l u e i n a s s e s s i n g r e l a t i o n s h i p s between t a x a . D i f f e r e n c e s i n base number, p l o i d y l e v e l , o r chromosomal s t r u c t u r e and b e h a v i o u r a r e not o n l y v a l u a b l e c h a r a c t e r s i n t h e m s e l v e s , but a l s o i n d i c a t e b r e e d i n g b a r r i e r s which may be a s s o c i a t e d w i t h d i a g n o s t i c a l l y u s e f u l but p r e v i o u s l y o v e r l o o k e d m o r p h o l o g i c a l d i f f e r e n c e s ( V a l e n t i n e & Love 1958). S t u d i e s which have made good use o f chromosomal data i n c l u d e t h o s e o f McKelvey & Sax (1933) on Yucca and Agave, Wagner (1954) on A p p a l a c h i a n A s p l e n i u m s p e c i e s , and R a j h a t h y & Thomas (1974) on Avena. Amongst the r e l a t i v e s o f H i e r a c i u m , s e v e r a l genera have been c y t o g e n e t -i c a l l y i n v e s t i g a t e d . Perhaps the b e s t known s t u d y has been done on the c l o s e l y r e l a t e d genus C r e p i s (Babcock & Cameron 1934, Babcock 1942, Babcock & J e n k i n s 1943). Ownbey (1950) found an i n t e r e s t i n g c o m b i n a t i o n o f h y b r i d i z a t i o n and p o l y p l o i d y i n Tragopogon. More r e c e n t l y , H s i e h e t a l (1972) have i n v e s t i g a t e d t he chromosomal b e h a v i o u r o f s e v e r a l s p e c i e s and a r t i f i c i a l h y b r i d s o f Sonchus. In t h i s s t u d y , both m i t o t i c and m e i o t i c chromosomes were examined i n each o f seven s p e c i e s o f H i e r a c i u m . Methods. Root t i p s f o r e x a m i n a t i o n o f m i t o s i s were c o l l e c t e d from p o t t e d p l a n t s e i t h e r t r a n s p l a n t e d d i r e c t l y from the w i l d , o r grown from s e e d . Some f l o w e r bud c o l l e c t i o n s were o b t a i n e d from t h e s e p l a n t s a l s o , but most buds were c o l l e c t e d i n the f i e l d . C o l l e c t i o n l o c a t i o n s f o r a l l p l a n t m a t e r i a l a r e - 70 -g i v e n i n T a b l e V I I . Voucher specimens f o r a l l c y t o l o g i c a l d e t e r m i n a t i o n s have been d e p o s i t e d i i n t h e U n i v e r s i t y o f B r i t i s h Columbia Herbarium. Both r o o t t i p s and buds gave b e s t r e s u l t s when c o l l e c t e d i n the morning (9:00 t o 11:00 a.m.). Root t i p s were c o l l e c t e d i n t o s m a l l v i a l s o f c o l d d i s t i l l e d water. A p r e - f i x a t i o n t r e a t m e n t w i t h a-bromonaphthalene (one dro p p er v i a l ) f o r t h r e e t o f o u r h ours a t 5°C was used t o c o n t r a c t t h e chromosomes and s e p a r a t e them from one a n o t h e r . The r o o t t i p s were then f i x e d i n e t h a n o l - a c e t i c a c i d ( 3 : 1 ) . S t o r a g e i n the f i x a t i v e f o r up t o s i x months caused o n l y s l i g h t d e t e r i o r a t i o n i n t h e q u a l i t y o f t h e squashes o b t a i n e d . For l o n g e r s t o r a g e t h e r o o t s were t r a n s f e r r e d t o 70% e t h a n o l . M a t e r i a l t o be examined was h y d r o l y s e d f o r t e n mi n u t e s i n 1 N HC1 a t 60°C, s t a i n e d i n l e u c o - b a s i c f u c h s i n f o r one t o two h o u r s , and squashed on a s l i d e i n 45% a c e t i c a c i d ( s e e t h e Fe u l g e n squash method o f D a r l i n g t o n & La Cour 1960, p. 156). Unopened f l o w e r heads one t o f i v e mm i n d i a m e t e r were c o l l e c t e d d i r e c t l y i n t o v i a l s c o n t a i n i n g Carnoy's f i x a t i v e ( e t h a n o l , c h l o r o f o r m and a c e t i c a c i d 6:3:1) ( D a r l i n g t o n & La Cour 1960, p. 141). They were f i x e d 24 t o 48 h o u r s , r i n s e d i n two o r t h r e e changes o f 70% e t h a n o l , t h e n s t o r e d i n 70% e t h a n o l . The buds were s t a i n e d i n Snow's a l c o h o l i c h y d r o c h l o r i c a c i d - c a r m i n e s t a i n (Snow 1963) f o r two t o t h r e e days. The a n t h e r s were d i s s e c t e d o u t from t h e i n d i v i d u a l f l o r e t s and squashed i n 45% a c e t i c a c i d . D i v i d i n g c e l l s i n both buds and r o o t t i p s were photographed u s i n g phase c o n t r a s t on a Z e i s s P h o t o m i c r o s c o p e I I . S l i d e s were made permanent by T a b l e V I I . C o l l e c t i o n s i t e s o f p l a n t m a t e r i a l used f o r chromosome s t u d i e s . S p e c i e s C o l l e c t i o n number M a t e r i a l c o l l e c t e d L o c a l i t y H. umbellatum 83, 364 87 92, 140 122 146 150 153 155, 158 160 buds, seed and l i v e p l a n t s buds seed seed l i v e p l a n t l i v e p l a n t l i v e p l a n t l i v e p l a n t s l i v e p l a n t Dry r o a d c u t a l o n g road i n t o B o t a n i e V a l l e y , f i v e t o s i x m i l e s n o r t h o f L y t t o n . D i s t u r b e d s o i l a l o n g d i r t road a t edge o f Mara Meadows, n o r t h e a s t o f Vernon. A l o n g road c l e a r a n c e on H o p e - P r i n c e t o n Highway, one m i l e e a s t o f Sunday Summit. Roadside a l o n g r o a d t o P a i n t e d Chasm ( l e a v i n g Highway 97 f i f t e e n m i l e s n o r t h o f C I i n t o n ) . D i s t u r b e d a r e a a l o n g r o a d s i d e n e a r a r o a d t u r n o f f , one t o two m i l e s e a s t o f Bonanza Pass on Highway 3. A l o n g r o a d c l e a r a n c e and f o r e s t edge t h r e e t o f o u r m i l e s west o f K i n n a i r d on Highway 3. Rocky b l u f f a t r o a d s i d e , one m i l e west o f N e l s o n on Highway 3. Dry bank w i t h P i n u s ponderosa and Pseudotsuga  m e n z i e s i i , e i g h t m i l e s e a s t o f N e l s o n on west arm o f Kootenay Lake. F o r e s t c l e a r i n g near t u f a d e p o s i t , 2.7 m i l e s west o f K a s l o on r o a d t o New Denver. ^ 1 1 c o l l e c t i o n numbers n o t p r e f i x e d by a l e t t e r code a r e mine. T a b l e V I I . ( c o n t ' d ) S p e c i e s Col l e c t i o n number M a t e r i a l c o l l e c t e d L o c a l i t y H. umbellatum ( c o n t ' d ) H. a l b e r t i n u m 2RLT 6184 207 259, 260 282 3ARGS 1624 13, 14, 16, 17, 22 272 163, 165, 166 l i v e p l a n t s seed l i v e p l a n t buds buds se e d seed buds Gr a v e l bank a l o n g r o a d s i d e , on e a s t s i d e o f Kootenay Lake 8.8 m i l e s n o r t h o f B o s w e l l , C l e a r i n g i n Douglas F i r - A s p e n f o r e s t , 10.3 m i l e s n o r t h o f A l k a l i Lake Post O f f i c e on roa d t o W i l l i a m s Lake. A l o n g r o a d s i d e one m i l e e a s t o f t u r n o f f t o Apex Mountain S k i A r e a , on Green Mountain Road west o f P e n t i c t o n . A l o n g f o r e s t edge and i n c l e a r i n g s , i n S y r i n g a Creek Campsite a t the s o u t h end o f Arrow Lake. Road c u t 4.5 m i l e s west o f N e l s o n , a l o n g Highway 3A. V i c i n i t y o f Anchorage, A l a s k a ( c o l l e c t e d by Mrs. L. S t r u t z , 916 P S t r e e t , Anchorage) S u b a l p i n e meadows on Morgan Mo u n t a i n , west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n ( e l e v . 4500'-5000'). Dry r o a d s i d e a l o n g Highway 6, 20 m i l e s s o u t h o f S l o c a n . ' C o l l e c t e d by Roy L. T a y l o r . O b t a i n e d t h r o u g h t he 1972 seed l i s t o f the American Rock Garden S o c i e t y . T a b l e V I I . ( c o n t ' d ) C o l l e c t i o n M a t e r i a l S p e c i e s number c o l l e c t e d H_. c y n o g l o s s o i d e s 33, 406 buds 142 l i v e p l a n t 145 l i v e p l a n t 193, 194 buds 267 buds 405 l i v e p l a n t H_. s c o u l e r i 3-9 x seed 38, 52 seed L o c a l i t y S u b a l p i n e meadows on Morgan Mountain, west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n ( e l e v . 4500'-5000'). Rocky f i e l d w i t h P i n u s ponderosa and Quercus  g a r r y a n a , near Satus Pass on Highway 97 n o r t h o f G o l d e n d a l e , K l i c k i t a t County, Washington S t a t e . ( C o l l e c t e d by Nancy J . T u r n e r . ) Dry open f i e l d w i t h Pseudotsuga m e n z i e s i i and Pinus p o n d e r o s a , Johnstone Creek Campsite on Highway 3 e a s t o f Osoyoos. Very d r y h i l l s i d e w i t h s c a t t e r e d P i n u s  p o n d e r o s a , two m i l e s n o r t h o f L y t t o n on r o a d t o B o t a n i e V a l l e y . Dry r o a d s i d e 20 m i l e s s o u t h o f S l o c a n a l o n g Highway 6. Grassy f i e l d two m i l e s south o f E l k o , o f f Highway 93. Dry r o a d s i d e a l o n g road i n t o B o t a n i e V a l l e y , f i v e t o s i x m i l e s n o r t h o f L y t t o n . S u b a l p i n e meadows on Morgan Mountain, west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n ( e l e v . 4000'-4500'). T a b l e V I I . ( c o n t C o l l e c t i o n M a t e r i a l S p e c i e s number c o l l e c t e d H.. s c o u l e r i 46 buds ( c o n t ' d ) 204 buds H_. a l b i f l o r u m 3-9a t o s seed 169 buds 148 l i v e p l a n t 157 l i v e p l a n t 161 l i v e p l a n t 271 buds 276 buds L o c a l i t y S u b a l p i n e meadows on Morgan Mountain, west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n ( e l e v . 4000'-4500'). Grazed open h i l l s i d e , one m i l e from west end o f Green Mountain Road ( r o a d t o Apex Mountain) and 18 m i l e s e a s t o f Keremeos. Dry r o a d s i d e a l o n g r o a d i n t o B o t a n i e V a l l e y , f i v e t o s i x m i l e s n o r t h o f L y t t o n . Dry r o a d s i d e a l o n g r o a d i n t o B o t a n i e V a l l e y , f i v e t o s i x m i l e s n o r t h o f L y t t o n . D i s t u r b e d zone a t r o a d s i d e , one t o two m i l e s e a s t o f Bonanza Pass on Highway 3. Dry bank w i t h P i n u s ponderosa and Pseudotsuga  m e n z i e s i i , e i g h t m i l e s e a s t o f N e l s o n on west arm o f Kootenay Lake. F o r e s t c l e a r i n g near t u f a d e p o s i t , 2.7 m i l e s west o f K a s l o on road t o New Denver. Roadside 20 m i l e s s o u t h o f S l o c a n , a l o n g Highway 6. Open woodland a t Lemon Creek P i c n i c Ground, seven t o e i g h t m i l e s s o u t h o f S l o c a n on Highway 6. T a b l e V I I . ( c o n t ' d ) C o l l e c t i o n M a t e r i a l S p e c i e s number c o l l e c t e d L o c a l i t y H. a l b i f l o r u m ( c o n t ' d ) 292 buds G r a v e l p i t a t end o f s m a l l s i d e r o a d , o f f Highway 3B j u s t s o uth o f i t s j u n c t i o n w i t h Highway 3. 306 buds D i s t u r b e d s o i l a t r o a d s i d e , a l o n g lower p a r t o f road t o B l a c k w a l l Meadows i n Manning P r o v i n c i a l Park. H. t r i s t e 384-88 seed Dry b l u f f a l o n g r o a d s i d e , f o u r t o f i v e m i l e s n o r t h o f M e z i a d i n Lake on S t e w a r t - C a s s i a r Road. H. g r a c i l e 128 seed Opening i n woods a l o n g road ( i n d i s t u r b e d s o i l ) , Mount Apex west o f P e n t i c t o n . 137 seed A l p i n e meadow on Mount Seymour, N o r t h Vancouver. ( C o l l e c t e d by Nancy J . T u r n e r . ) 141 seed A l p i n e meadows, I l g a c h u z Range n o r t h o f Anahim Lake. ( C o l l e c t e d by Roy L. T a y l o r . ) N a t u r a l h y b r i d s : f i - a l b e r t i n u m X H. a l b i f l o r u m 22 4 s e e d S u b a l p i n e meadows on Morgan Mountain, west s i d e o f B o t a n i e V a l l e y n o r t h o f L y t t o n . l i - a l b i f l o r u m X H. g r a c i l e 389, 390, 391 buds D i s t u r b e d s o i l a l o n g r o a d s i d e , f o u r t o f i v e m i l e s n o r t h o f M e z i a d i n Lake on S t e w a r t - C a s s Road. ^ C o l l e c t e d from a p l a n t o f H_. a l b e r t i n u m . - 76 -f r e e z i n g w i t h compressed c a r b o n d i o x i d e (Bowen 1956), d e h y d r a t i n g i n a b s o l u t e e t h a n o l , and mounting i n Permount. R e s u l t s . (1) Chromosome number. The base number f o r the genus H i e r a c i u m i s x = 9. Chromosome c o u n t s have p r e v i o u s l y been o b t a i n e d f o r most o f t h e s p e c i e s d i s c u s s e d h e r e . H i e r a c i u m g r a c i l e f r o m w e s t e r n N o r t h America has been c o u n t e d by S t e b b i n s e t a l (1953 ) , K r u c k e b e r g ( 1 9 6 7 ) , T a y l o r & M u l l i g a n (1968) and P o j a r (1973). H i e r a c i u m t r i s t e has been c o u n t e d t w i c e f r o m t h e e a s t e r n U. S. S. R. ( S o k o l o v s k a y a 1963, 1968) and once f r o m t he Queen C h a r l o t t e I s l a n d s ( T a y l o r & M u l l i g a n 1968). Four r e p o r t s have appeared f o r H. a l b i f l o r u m ( S t e b b i n s e t al_ 1953, K r u c k e b e r g 1967, T a y l o r & M u l l i g a n 1968, and Wi t h e r s p o o n e t a l 1974) and one f o r H. c y n o g l o s s o i d e s (Schaack e_t al_ 1974). A s i n g l e c o u n t has a l s o been made o f ti. s c o u l i e r i (Roy L. T a y l o r , p e r s o n a l commun-i c a t i o n ) . For a l l o f t h e s e s p e c i e s t he d i p l o i d number o f chromosomes was e i g h t e e n . Chromosome.counts f o r H. umbellatum have been p u b l i s h e d by a t l e a s t e i g h t e e n d i f f e r e n t a u t h o r s ( s e e B o l k h o v s k i k h e t al_ 1969 and Moore 1973), but o n l y from European and A s i a n m a t e r i a l . Most o f t h e r e p o r t s g i v e 2n = 18. Counts o f 2n - 1 8 and 2n = 27, both from Europe, have been p u b l i s h e d by Rosenberg (1926 and 1927), T i s c h l e r ( 1 9 3 4 ) , Bergman (1935) and Rohweder (1937). S t i l l h i g h e r c o u n t s a r e known i n r e l a t e d s p e c i e s o f t h e subgenus E u h i e r a c i u m . S o k o l o v s k a y a (1963, 1965) c o l l e c t e d H_. umbel!atum i n two d i f f e r e n t a r e a s i n the e a s t e r n U. S. S. R., and found o n l y t r i p l o i d s . - 77 -H i e r a c i u m canadense, which i s found o n l y i n North A m e r i c a , has been c o u n t e d t w i c e ( G u s t a f s o n 1933, G e n t c h e f f 1937). In both c a s e s the m a t e r i a l was t r i p l o i d . Zahn (1921-1923) c o n s i d e r e d H_. canadense t o be a s u b s p e c i e s o f t h e European H,. l a e v i g a t u m W i l l d . , and the l a t t e r s p e c i e s i s a l s o known o n l y as a t r i p l o i d (Rosenberg 1917 and 1927, C h r i s t o f f & P o p o f f 1933, G a d e l l a & K l i p h u i s 1966). In t h i s s t u d y , s i x t o e i g h t e e n p l a n t s were c o u n t e d f o r each o f t h e s p e c i e s o f the subgenus S t e n o t h e c a ( e x c e p t f o r t r i s t e : two p l a n t s ) . In a l l c a s e s the chromosome number was 2n = 18 ( o r n = 9 ) . The c o u n t f o r H. a l b e r t i n u m F a r r i s r e p o r t e d here f o r t h e f i r s t t ime. In the subgenus E u h i e r a c i u m , o n l y H_. umbel!atum was c o u n t e d , as no t y p i c a l m a t e r i a l o f H. canadense was o b t a i n e d ( a l t h o u g h some o f the specimens o f H_. umbellatum tended s l i g h t l y toward HL canadense i n t h e i r m o r p h o l o g i c a l c h a r a c t e r i s t i c s ) . Counts were o b t a i n e d from 27 p l a n t s o f JH. umbel l a t u m ; a l l o f t h e s e were t r i p l o i d , w i t h 2n = 27. (2) K a r y o t y p e . R e p r e s e n t a t i v e k a r y o t y p e s o f each s p e c i e s ( a r r a n g e d i n the s t a n d a r d manner, f r o m l a r g e s t chromosome p a i r t o s m a l l e s t ) a r e p r e s e n t e d i n P l a t e s 5 to 12. The chromosomes a r e r o u g h l y s i m i l a r i n s i z e and t h e y v a r y from about t h r e e t o a b o u t seven m i c r o n s i n l e n g t h . The k a r y o t y p e s o f t h e s p e c i e s o f subgenus S t e n o t h e c a ( P l a t e s 7 t o 12) a r e v e r y s i m i l a r . A l l the chromosomes have median o r submedian c e n t r o m e r e s . S a t e l l i t e s were u s u a l l y v i s i b l e on a t l e a s t one chromosome p a i r and sometimes on two. Two p a i r s o f SAT chromosomes can be seen i n each o f P l a t e s 7, 10, 11 and 12. - 78 -lie » t m M m lit in MI II* 10 M P l a t e 5. K a r y o t y p e o f H i e r a c i u m umbellatum ( c o l l e c t i o n no. 207). m m m w HI HI in in HI 10 M P l a t e 6. K a r y o t y p e o f H i e r a c i u m umbellatum ( c o l l e c t i o n no. 122a). - 79 -II K (( II H )i It K >i 10 M P l a t e 7. K a r y o t y p e o f H i e r a c i u m a l b e r t i n u m ( c o l l e c t i o n no. 1 4 c ) . n ti u it )t it it i i k 10 M P l a t e 8. K a r y o t y p e o f H i e r a c i u m c y n o g l o s s o i d e s ( c o l l e c t i o n no. 406). - 80 -II II II II II M II H II 10 M P l a t e 9. K a r y o t y p e o f H i e r a c i u m s c o u l e r i ( c o l l e c t i o n no. 52a). )( II II II II II il It it 10 y P l a t e 10. K a r y o t y p e o f H i e r a c i u m a l b i f l o r u m ( c o l l e c t i o n no. 3 - 9 j ) . - 81 -II II II f( ID It fl tt 10 M P l a t e 11. K a r y o t y p e o f H i e r a c i u m t r i s t e ( c o l l e c t i o n no. 384-88a). )) II H | | l( H II II P l a t e 12. K a r y o t y p e o f H i e r a c i u m g r a c i l e ( c o l l e c t i o n no. 1 4 1 j ) . - 82 -The k a r y o t y p e o f H. umbellatum d i f f e r s somewhat from t h o s e o f t h e o t h e r s p e c i e s . The l a r g e s t chromosomes have a median r a t h e r than submedian c e n t r o m e r e , and some o f the s m a l l e r chromosomes have more unequal arms. T h i s s p e c i e s has two groups o f s a t e l l i t e chromosomes, as do members o f t h e subgenus S t e n o t h e c a , but one group o f s a t e l l i t e s i s much l a r g e r than the o t h e r ( i n p a r t i c u l a r see t h e t h i r d t r i p l e t o f chromosomes i n P l a t e 6 ) . In the o t h e r s p e c i e s t h e two p a i r s o f s a t e l l i t e s a r e the same s i z e . C l e a r l y t h e k a r y o t y p e i s o f l i t t l e v a l u e as a taxonomic t o o l i n t h i s group. H i e r a c i u m umbellatum and t h e o t h e r s i x s p e c i e s b e l o n g t o d i f f e r e n t subgenera and a r e q u i t e d i f f e r e n t m o r p h o l o g i c a l l y , but the d i f f e r e n c e s i n chromosome s i z e and shape a r e v e r y s m a l l . W i t h i n t h e subgenus S t e n o t h e c a , a t l e a s t among t h e s p e c i e s found i n B r i t i s h Columbia, the k a r y o t y p e s c a n n o t be d i s t i n g u i s h e d . Two o f t h e a r t i f i c i a l l y g e n e r a t e d h y b r i d s d e s c r i b e d i n C h a p t e r I I I (jj_. a l b i f l o r u m X JH_. c y n o g l o s s o i d e s , and H_. g r a c i l e X H_. s c o u l e r i ) were examined i n a d d i t i o n t o the s p e c i e s . T h e i r k a r y o t y p e s were found t o be i n d i s t i n g u i s h a b l e from t h o s e o f t h e i r r e s p e c t i v e p a r e n t s . S l i g h t v a r i a t i o n s i n s i z e and shape o f chromosomes were o b s e r v e d i n a l l the s p e c i e s examined, both w i t h i n t a x a and w i t h i n i n d i v i d u a l p l a n t s . A c e r t a i n amount o f s t r e t c h i n g o r d e f o r m a t i o n , which o c c u r r e d d u r i n g s q u a s h i n g , was a p p a r e n t upon comparison o f homologous chromosomes. In t h e m a t e r i a l examined t h e r e were a l s o s l i g h t d i f f e r e n c e s i n the s t a g e o f d i v i s i o n . I o r d a n s k y et_ a]_ (1975) found t h a t i n some Al 1 iurn s p e c i e s , t h e r e l a t i v e l e n g t h s o f d i f f e r e n t chromosomes changed a c c o r d i n g t o the degree o f c o n t r a c t i o n o f the genome. T h i s c o u l d a c c o u n t f o r a l l o f t h e o b s e r v e d i n t r a s p e c i f i c - 83 -v a r i a t i o n i n chromosome l e n g t h and s t r u c t u r e t h a t was e n c o u n t e r e d d u r i n g the p r e s e n t s t u d y . (3) M e i o s i s . To d e t e r m i n e m e i o t i c b e h a v i o u r , m e i o s i s was o b s e r v e d i n the p o l l e n mother c e l l s o f each s p e c i e s . M e i o s i s has been s t u d i e d i n v a r i o u s s p e c i e s o f the subgenus E u h i e r a c i u m by a number o f European workers (Rosenberg 1917 and 1927, C h r i s t o f f 1940, G u s t a f s s o n & Nygren 1946, G u s t a f s s o n 1946-47). Emphasis has been on m e i o s i s i n t h e megasporocyte, but p o l l e n mother c e l l s have been s t u d i e d a l s o . In H i e r a c i u m umbellatum, p o l y p l o i d a p o m i c t s have been examined by Bergman (1935), and G e n t c h e f f (1941) found an a p o m i c t t h a t was d i p l o i d . A c c o r d i n g to Rosenberg ( 1 9 2 7 ) , w i t h i n the subgenus E u h i e r a c i u m the d i v i s i o n s o f the p o l l e n mother c e l l s o f a p o m i c t i c s p e c i e s a r e o f t h r e e t y p e s : (a) the H i e r a c i u m b o r e a l e t y p e -- a t m e i o s i s , v a r y i n g numbers o f b i v a l e n t s (and t r i v a l e n t s , i f the p l a n t i s t r i p l o i d ) a p p e a r , t o g e t h e r w i t h some u n i v a l e n t s . (b) the JH. l a e v i g a t u m t y p e -- m e i o s i s i s c h a r a c t e r i z e d by complete a s y n a p s i s . ( c ) the JH. p s e u d o i l l y r i c u m t y p e -- a t e a r l y prophase t h e n u c l e u s c o n t r a c t s , and m e i o s i s i s r e p l a c e d by a d i v i s i o n c l o s e l y r e s e m b l i n g m i t o s i s . A l l t h e s e t y p e s can o c c u r i n a s i n g l e f l o w e r head. Rosenberg (1927) o b s e r v e d heads i n which t h e p o l l e n mother c e l l s o f t h e c e n t r a l f l o r e t s were s m a l l , and d u r i n g m e i o s i s t h e r e was complete l a c k o f s y n a p s i s , w h i l e t h e - 84 -p o l l e n mother c e l l s o f the o u t e r f l o r e t s were l a r g e r and showed b i v a l e n t f o r m a t i o n . In the t r i p l o i d H i e r a c i u m umbellatum o b s e r v e d by Bergman ( 1 9 3 5 ) , s e v e r a l t r i v a l e n t s were p r e s e n t . The d i p l o i d a p o m i c t s t u d i e d by G e n t c h e f f (1941) underwent a m o d i f i e d m i t o s i s o f t h e IH. p s e u d o i l l y r i c u m t y p e . In the p r e s e n t s t u d y both b i v a l e n t s and t r i v a l e n t s were o b s e r v e d i n H_. umbel!atum (see P l a t e s 13 t o 1 5 ) , and m e i o s i s i n t h e a n t h e r s a p p e a r s t o be o f the H_. boreal.e.type. A t l e a s t a few u n i v a l e n t s were always s e e n , and some c e l l s c o n t a i n e d o n l y u n p a i r e d chromosomes. P l a t e 16 shows t h e unequal d i s t r i b u t i o n o f chromosomes t h a t i s usual a t Anaphase I. G u s t a f s o n ( 1 9 3 3 ) , s t u d y i n g H,. canadense from e a s t e r n N o r t h A m e r i c a , f o u n d a s i m i l a r p a t t e r n . P a i r i n g was v e r y i r r e g u l a r and the number o f b i v a l e n t s v a r i e d from t w e l v e t o none ( i n c o n t r a s t t o t h e European s p e c i e s H_. l a e v i g a t u m , w i t h complete l a c k o f p a i r i n g ) . No t r i v a l e n t s were r e p o r t e d , though H_. canadense i s t r i p l o i d . G u s t a f s o n found t h a t some c e l l s i n the a n t h e r s produced a t e t r a d o f p o l l e n g r a i n s , w h i l e o t h e r s formed a " r e s t i t u t i o n n u c l e u s " o f t h e t y p e d e s c r i b e d by Rosenberg (1917) which u l t i m a t e l y r e s u l t e d i n a p o l l e n g r a i n dyad. A l t h o u g h I d i d n o t o b s e r v e t h i s i n H_. umbel!atum , a number o f t h e p o l l e n mother c e l l s appeared abnormal. Many o f t h e p o l l e n g r a i n s p r o b a b l y l a c k e d a complete genome. A l s o , whereas i n s e x u a l s p e c i e s o f t h e subgenus E u h i e r a c i u m a b a l a n c e e x i s t s between t h e growth r a t e s o f the p o l l e n mother c e l l s and t h e t a p e t a l c e l l s , i n a p o m i c t s t h e p o l l e n mother c e l l s o f t e n d e v e l o p p r e c o c i o u s l y ( G e n t c h e f f & G u s t a f s s o n 1940). The more s l o w l y d e v e l o p i n g t a p e t a l c e l l s c a n n o t p r o v i d e adequate n u t r i e n t , and t h i s l e a d s t o abnormal development o f t h e p o l l e n g r a i n s . 85 P l a t e 13. M e i o s i s ( d i a k i n e s i s ) i n p o l l e n mother c e l l s o f H i e r a c i u m  umbellatum ( c o l l e c t i o n no. 259). Note the p o s s i b l e t r i v a l e n t c o n f i g u r a t i o n s a t t h i s s t a g e . M P l a t e 15. Metaphase I i n H i e r a c i u m  umbel l a t u m ( c o l l e c t i o n no. 150). Note t r i v a l e n t s . P l a t e 14. Metaphase I i n H i e r a c i u m  umbel l a t u m ( c o l l e c t i o n no. 150). Note the t r i v a l e n t i n d i c a t e d by t h e arrow. P l a t e 16. Anaphase I i n H i e r a c i u m  umbellatum ( c o l l e c t i o n no. 153) showing unequal d i s t r i b u t i o n o f chromosomes between d a u g h t e r c e l l s . - 86 -H i e r a c i u m canadense and JH. umbellatum i n N o r t h America a r e c l e a r l y as s i m i l a r as t h e l a c k o f r e l i a b l e m o r p h o l o g i c a l d i f f e r e n c e s between them would s u g g e s t , and t h e y p r o b a b l y have a r e c e n t common o r i g i n . In the c y t o l o g i c a l m a t e r i a l shown h e r e , a number o f t r i v a l e n t chromosome c o n f i g u r a t i o n s a r e v i s i b l e ( P l a t e s 13 t o 15). T h i s c o u l d be c o n s i d e r e d an i n d i c a t i o n o f a u t o p l o i d y . The p r e s e n c e o f m u l t i v a l e n t s i s n o t t y p i c a l o f a l l a u t o p l o i d s , however. G u s t a f s s o n (1947) c o n s i d e r e d t h a t o n l y r a r e l y was a s y n a p s i s i n a p o m i c t i c s p e c i e s an i n d i c a t i o n o f l a c k o f homology between t h e chromosomes. Lack o f p a i r i n g d u r i n g m e i o s i s i s a p p a r e n t l y under g e n e t i c c o n t r o l , e s p e c i a l l y i n the m e g a s p o r o c y t e s . C h r i s t o f f (1940) used c o l c h i c i n e t o d o u b l e the chromosome number ( f r o m 2n = 27 t o 2n = 54) i n the a p o m i c t i c s p e c i e s H_. gothicum. The h e x a p l o i d showed the same complete l a c k o f p a i r i n g f o u n d i n the t r i p l o i d . In the subgenus S t e n o t h e c a , a p o m i x i s i s p r e s e n t l y unknown. C r o n q u i s t (195.5a) s u g g e s t e d t h a t H i e r a c i u m c y n o g l o s s o i d e s , the m o r p h o l o g i c a l l y i n t e r m e d i a t e s p e c i e s o f the H_. s c o u l e r i complex, might be "a s e r i e s o f p o l y p l o i d a p o m i c t s o r i g i n a t i n g from h y b r i d i z a t i o n between H_. a l b e r t i n u m and JH. s c o u l e r i " . The r e s u l t s p r e s e n t e d here show t h i s h y p o t h e s i s t o be i n c o r r e c t . I t can be seen from P l a t e s 17 t o 28 t h a t m e i o s i s i s r e g u l a r i n a l l s i x o f the s p e c i e s o f t h i s subgenus t h a t were i n c l u d e d i n t h i s s t u d y . Two t o s i x d i f f e r e n t p l a n t s o f each s p e c i e s were examined, and no m e i o t i c a b n o r m a l i t i e s were o b s e r v e d . F i v e o t h e r H i e r a c i u m s p e c i e s , o c c u r r i n g i n the western U n i t e d S t a t e s and c l o s e l y r e l a t e d t o t h e JH. s c o u l e r i complex, remain t o be s t u d i e d . I t - 87 -P l a t e 17. D i a k i n e s i s i n H i e r a c i u m P l a t e 18. Metaphase I i n H i e r a c i u m a l b e r t i n u m ( c o l l e c t i o n no. 272). a l b e r t i n u m ( c o l l e c t i o n no. 272). * * -P l a t e 19. D i a k i n e s i s i n H i e r a c i u m  c y n o g l o s s o i d e s ( c o l l e c t i o n no. 3 3 ] T P l a t e 20. Metaphase I i n H i e r a c i u m  c y n o g l o s s o i d e s ( c o l l e c t i o n no. 33). - 88 -P l a t e 21. D i a k i n e s i s i n H i e r a c i u m  s c o u l e r i ( c o l l e c t i o n no. 313). P l a t e 23. D i a k i n e s i s i n H i e r a c i u m  a l b i f l o r u m ( c o l l e c t i o n no. 169). P l a t e 22. Metaphase I i n H i e r a c i u m  s c o u l e r i ( c o l l e c t i o n no. 204). Note the s p i n d l e f i b r e s . P l a t e 24. Metaphase I i n H i e r a c i u m  a l b i f l o r u m ( c o l l e c t i o n no. 306). - 89 -P l a t e 27. D i a k i n e s i s i n H i e r a c i u m P l a t e 28. Metaphase I i n H i e r a c i u m g r a c i l e ( c o l l e c t i o n no. 1 4 1 c c ) . g r a c i l e ( c o l l e c t i o n no. 1 4 1 c c ) . ( T h i s specimen tended toward JH. t r i s t e . ) - 90 -seems l i k e l y t h a t t h e s e t a x a a r e s i m i l a r i n chromosomal b e h a v i o u r t o the s p e c i e s a l r e a d y i n v e s t i g a t e d , but good e v i d e n c e o f t h i s i s s t i l l t o be g a t h e r e d . The a p p a r e n t absence o f a p o m i x i s i n t h e subgenus S t e n o t h e c a i s i n t e r e s t i n g i n view o f t h e p r e v a l e n c e o f t h i s phenomenon e l s e w h e r e i n t h e genus. M e i o s i s was a l s o examined i n the a r t i f i c i a l l y produced c r o s s e s ( d e s c r i b e d i n C h a p t e r I I I ) between d i f f e r e n t s e c t i o n s o f t h i s subgenus. M e i o t i c d i v i s i o n s i n t h e p o l l e n mother c e l l s a r e shown i n P l a t e s 29 t o 32. A l l t h r e e o f t h e i n t e r s e c t i o n a l h y b r i d s d i s p l a y e d c o m p l e t e l y r e g u l a r m e i o s i s . T h i s i n d i c a t e s a h i g h degree o f chromosome homology, and i s o f c o n s i d e r a b l e i n t e r e s t , s i n c e the s p e c i e s i n v o l v e d ( e s p e c i a l l y g r a c i l e ) a r e m o r p h o l o g i c a l l y d i s t i n c t . I t seems l i k e l y t h a t t h e r e a r e many s m a l l r e g i o n s o f the d i f f e r e n t genomes t h a t a r e not homologous, and t h i s would a c c o u n t f o r the somewhat low e r e d p o l l e n f e r t i l i t y o f the h y b r i d s . However, the chromosomes a r e s u f f i c i e n t l y s i m i l a r t o form p a i r s . C l e a r l y t h e s e s p e c i e s a r e more c l o s e l y r e l a t e d than has so f a r been r e a l i z e d . 91 P l a t e 29. D i a k i n e s i s i n p o l l e n mother c e l l s o f H i e r a c i u m a l b i f l o r u m X H. a l b e r t i n u m . P l a t e 30. Metaphase I i n H i e r a c i u m  a l b i f l o r u m X H_. a l b e r t i n u m . Note t h a t one chromosome p a i r i s sep-a r a t i n g s l i g h t l y ahead o f the o t h e r s . T h i s was o b s e r v e d o f t e n i n a l l t h e s p e c i e s o f t h e subgenus S t e n o t h e c a . P l a t e 31. Metaphase I i n H i e r a c i u m  g r a c i l e X H. s c o u l e r i . P l a t e 32. Metaphase I i n H i e r a c i u m  g r a c i l e X H_. a l b i f l o r u m . - 92 -V. FLAVONOID CHEMISTRY In r e c e n t y e a r s , c h e m i c a l d a t a have been used w i t h i n c r e a s i n g f r e q u e n c y t o h e l p s o l v e taxonomic problems. Among t h e most v a l u a b l e compounds f o r t h i s purpose a r e the f l a v o n o i d s . They f u l f i l l a l l the r e q u i r e m e n t s f o r taxonomic u s e f u l n e s s (Harborne 1967): t h e y a r e r e l a t i v e l y s t a b l e both b i o c h e m i c a l l y and e c o l o g i c a l l y , t h e y o c c u r w i d e l y i n p l a n t s , t h e y e x h i b i t g r e a t s t r u c t u r a l v a r i a b i l i t y , and t h e y a r e q u i c k l y and e a s i l y i d e n t i f i e d . A number o f s t u d i e s have shown the v a l u e o f f l a v o n o i d s as a t o o l f o r d i s t i n g u i s h i n g between s p e c i e s o r d e t e c t i n g h y b r i d s . Among t h e groups t h a t have been s t u d i e d a r e t h e A p p a l a c h i a n A s p l e n i u m complex ( S m i t h & L e v i n 1963, Harborne e t al_ 1973), the Lemnaceae ( M c C l u r e & A l s t o n 1966), and the genus B a p t i s i a ( A l s t o n & T u r n e r 1963, A l s t o n e t al_ 1965). P h e n o l i c compounds i n the genus H i e r a c i u m have not been e x t e n s i v e l y i n v e s t i g a t e d . S e v e r a l s p e c i e s have been s u r v e y e d by B a t e - S m i t h ejt al_ (1968) f o r t h e c o u m a r i n , umbel 1 i f e r o n e . However, o n l y a few r e p o r t s on the f l a v o n o i d s i n the genus have been p u b l i s h e d t o d a t e . Horhammer & Wagner (1962) found l u t e o l i n 7 - 0 - g l u c o s i d e i n H i e r a c i u m s t a t i c i f o l i u m and H. p i l o s e l l a . H a a g - B e r r u r i e r & Duquenois (1969) showed the p r e s e n c e o f a p i g e n i n , l u t e o l i n , l u t e o l i n 7 - 0 - 3 - D - g l u c o s i d e and l u t e o l i n 7 - 0 - d i g l u c o s i d e , as w e l l as s e v e r a l o t h e r u n i d e n t i f i e d f l a v o n o i d s , i n H_. murorum L. s s p . g r a n d i d e n s v a r . m i n o r i c e p s . In t h i s s t u d y , a t w o - d i m e n s i o n a l chromatogram showing t h e a r r a y o f f l a v o n o i d s was p r e p a r e d f o r each o f t h e s p e c i e s , and f o r t h r e e i n t e r s p e c i f i c h y b r i d s . F i v e o f t h e s p e c i e s were c h e m i c a l l y a n a l y z e d and t h e i r f l a v o n o i d s - 93 -i d e n t i f i e d . The s o u r c e s o f a l l t h e m a t e r i a l used a r e l i s t e d i n T a b l e V I I I . Voucher s p e c i m e n s , where n e c e s s a r y , have been d e p o s i t e d i n the U n i v e r s i t y o f B r i t i s h Columbia Herbarium. Methods. Whole p l a n t s were c o l l e c t e d d u r i n g t h e summer o f 1972, d r i e d , and s t o r e d u n t i l needed. For i d e n t i f i c a t i o n o f f l a v o n o i d s , a p p r o x i m a t e l y 200 t o 300 grams o f d r i e d p l a n t m a t e r i a l , w a s used f o r each s p e c i e s ; t w o - d i m e n s i o n a l maps were p r e p a r e d e i t h e r from t h e s e l a r g e e x t r a c t s o r from a d d i t i o n a l s i n g l e specimens. The p l a n t m a t e r i a l was crumbled and then e x t r a c t e d w i t h t h r e e o r f o u r changes o f b o i l i n g 80% e t h a n o l o r methanol. The combined e x t r a c t was r e d u c e d t o a sma l l volume on a r o t a r y e v a p o r a t o r , taken up i n b o i l i n g w ater, t r e a t e d w i t h C e l i t e a n a l y t i c a l f i l t e r a i d , and f i l t e r e d under vacuum. The r e s i d u e was washed w i t h s m a l l amounts o f b o i l i n g water u n t i l t h e f i l t r a t e was c l e a r . The f i l t r a t e was c o n t i n u o u s l y e x t r a c t e d w i t h e t h y l a c e t a t e f o r 36 t o 48 ho u r s ; t h i s removed most o f the f l a v o n o i d s p r e s e n t . A f u r t h e r , s t e p w i s e e x t r a c t i o n o f the aqueous e x t r a c t w i t h 1-butanol was u s e f u l i n o b t a i n i n g b e t t e r y i e l d s o f v e r y p o l a r f l a v o n o i d s ( e . g . , f l u c u r o n i d e s ) . The aqueous e x t r a c t was d i s c a r d e d , and the 1-butanol and e t h y l a c e t a t e e x t r a c t s r e d u c e d to a sma l l volume. C o n c e n t r a t e d e x t r a c t s were s e p a r a t e d on a column packed w i t h P olyamide SC-6 1 o r Sephadex 2. F l a v o n o i d s were e l u t e d w i t h i n c r e a s i n g c o n c e n t r a t i o n s o f ^ f g . by Macherey, Nagel & Co. 2mfg. by Pharmacia L t d . T a b l e V I I I . S o u r c e s o f p l a n t m a t e r i a l used f o r c h e m i c a l a n a l y s e s . S p e c i e s C o l l e c t i o n number Source H_. umbel latum mass c o l l e c t i o n t w o - d i m e n s i o n a l c h r o m a t o g r a p h i c map H_. a l b e r t i n u m a l l m a t e r i a l H^ c y n o g l o s s o i d e s mass c o l l e c t i o n c h r o m a t o g r a p h i c map H. s c o u l e r i 122 153, 155 13-24 25-37 188 Roadside i n d r y c o n i f e r o u s f o r e s t , a l o n g r o a d t o Painteid Chasm, l e a v i n g Highway 97 f i f t e e n m i l e s n o r t h o f C l i n t o n . On shaded bank a l o n g r o a d , e i g h t m i l e s e a s t o f Ne l s o n . S u b a l p i n e meadow, B o t a n i e V a l l e y n o r t h o f L y t t o n . S u b a l p i n e meadow, B o t a n i e V a l l e y n o r t h o f L y t t o n . Dry h i l l s i d e i n Ponderosa P i n e - B u n c h g r a s s zone, two t o t h r e e m i l e s n o r t h o f L y t t o n on road i n t o B o t a n i e V a l l e y C h r o m a t o g r a p h i c map 40-53, 57-62 (combined) S u b a l p i n e meadow, B o t a n i e V a l l e y n o r t h o f L y t t o n , *The sample m a t e r i a l f o r ]1. t r i s t e was t a k e n from an her b a r i u m s h e e t . The h e r b a r i u m number o f t h e s h e e t i s t h e r e f o r e s u b s t i t u t e d f o r c o l l e c t i o n number. T a b l e V I I I . ( c o n t ' d ) S p e c i e s H_. a l b i f l o r u m mass c o l l e c t i o n H_. g r a c i l e a l l m a t e r i a l C o l l e c t i o n number c h r o m a t o g r a p h i c map 104-109 H. t r i s t e c h r o m a t o g r a p h i c map ALA #47382 397-403 Source 1-2, 3 t 8 , 84-86 Dry r o a d s i d e a l o n g road i n t o B o t a n i e V a l l e y ; a l s o r o a d s i d e near Summit Lake n o r t h o f P r i n c e George. Dry r o a d s i d e a l o n g road i n t o B o t a n i e V a l l e y , n o r t h o f L y t t o n . U n i v e r s i t y o f A l a s k a herbarium specimen ( c o l l e c t e d from g r a v e l l y , p e a t y s o i l near a r o a d s i d e , Amchitka I s l a n d , A l a s k a ) . A l p i n e meadows on Mt. A r r o w s m i t h , Vancouver I s l a n d , and on Mt. W i n c h e s t e r , Mount Baker N a t i o n a l F o r e s t , Washington. H y b r i d s A r t i f i c i a l h y b r i d i z a t i o n e x p e r i m e n t s . - 96 -methanol i n water ( 0 % t o 8 0 % ) . The columns were m o n i t o r e d by t h i n - l a y e r c hromatography, and column f r a c t i o n s p o o l e d where n e c e s s a r y and r e - r u n on s m a l l e r columns. F i n a l s e p a r a t i o n o f compounds was a c c o m p l i s h e d by r e p e a t e d chromatography on t h i n - l a y e r p l a t e s c o a t e d w i t h A v i c e l ( m i c r o c r y s t a l 1 i n e c e l l u l o s e ) o r Polyamide DC-6.6 3. The f o l l o w i n g s o l v e n t s were used: I. Water, 1 - b u t a n o l , a c e t o n e , d i o x a n e (70:15:10:5). Used on p o l y a m i d e . I I . Benzene, 2-butanone, methanol, water (55:22:20:3). Used on p o l y a m i d e . I I I . 15% a c e t i c a c i d . Used on A v i c e l . IV. Water, 2-butanone, a c e t o n e , f o r m i c a c i d (60:30:9:1). Used on p o l y a m i d e . U s e f u l f o r s e p a r a t i n g g l u c u r o n i d e s . V. C h l o r o f o r m , 2-butanone, methanol (70:15:15). Used on p o l y a m i d e . U s e f u l f o r s e p a r a t i n g a g l y c o n e s . Between each r u n , compounds were e l u t e d from t h e p l a t e a d s o r b e n t w i t h 90% a c e t o n e . H y d r o x y l a t i o n and g l y c o s y l a t i o n p a t t e r n s o f p u r i f i e d compounds were d e t e r m i n e d by a n a l y s i s o f the u l t r a v i o l e t a b s o r p t i o n s p e c t r u m (Mabry e t a l 1970). G l y c o s i d e s were s u b j e c t e d t o t o t a l h y d r o l y s i s by h e a t i n g w i t h 1 N h y d r o c h l o r i c a c i d f o r one hour a t 100°C. The a g l y c o n e was then e x t r a c t e d w i t h e t h y l a c e t a t e and i d e n t i f i e d by chromatography, t o g e t h e r w i t h s t a n d a r d a g l y c o n e s , i n s o l v e n t s II and V. The r e m a i n i n g s o l u t i o n , c o n t a i n i n g t h e s u g a r , was e v a p o r a t e d t o d r y n e s s and t r e a t e d w i t h N - m e t h y l - N , N - d i o c t y l a m i n e 3 A l s o mfg. by Macherey, Nagel & Co. - 97 -t o remove e x c e s s a c i d ( s e e Bohm e t a]_ 1974), f o l l o w e d by c h l o r o f o r m t o remove the amine. The su g a r was chromatographed, w i t h s t a n d a r d s , on p l a s t i c t h i n - l a y e r s t r i p s c o a t e d w i t h m i c r o c r y s t a l l i n e c e l l u l o s e . These were r u n i n e t h y l a c e t a t e , p y r i d i n e , water (10:3:2) and t h e su g a r was d e t e c t e d by s p r a y i n g w i t h p - a n i s i d i n e p h t h a l a t e , f o l l o w e d by h e a t i n g . The o r d e r o f sugar a t t a c h m e n t i n b i o s i d e s was d e t e r m i n e d by p a r t i a l h y d r o l y s i s w i t h 20% a c e t i c a c i d a t 100°C. The h y d r o l y s a t e was sampled a t i n t e r v a l s , and i n t e r m e d i a t e breakdown p r o d u c t s i d e n t i f i e d by chromatography w i t h s t a n d a r d s i n s o l v e n t s I t o I I I . In some c a s e s t h e s t r u c t u r e o f the i n t e r m e d i a t e was v e r i f i e d by t o t a l h y d r o l y s i s , and i d e n t i f i c a t i o n o f s u g a r and a g l y c o n e . When q u a n t i t i e s p e r m i t t e d , e n z y m a t i c h y d r o l y s i s was c a r r i e d o u t on g l u c o s i d e s and g l u c u r o n i d e s t o d e t e r m i n e which anomer o f the sugar was p r e s e n t . Compounds were i n c u b a t e d o v e r n i g h t w i t h e m u l s i n ( B - g l u c o s i d a s e ) i n 0.05 M a c e t a t e b u f f e r a t pH 5.0, o r w i t h B - g l u c u r o n i d a s e i n 0.01 M phosphate b u f f e r a t pH 6.85. H y d r o l y s i s p r o d u c t s were i d e n t i f i e d as p r e v i o u s l y d e s c r i b e d . Two-dimensional maps o f t h e f l a v o n o i d s o f each s p e c i e s were p r e p a r e d by ch r o m a t o g r a p h i n g s m a l l amounts o f c r u d e e t h y l a c e t a t e e x t r a c t on p o l y a m i d e t h i n - l a y e r p l a t e s , f i r s t i n s o l v e n t I and then i n s o l v e n t I I . The p l a t e s were s p r a y e d w i t h d i p h e n y l b o r i c a c i d 3-aminoethyl e s t e r . Under u l t r a v i o l e t l i g h t , t h i s r e a g e n t g i v e s s t r i k i n g and f r e q u e n t l y d i a g n o s t i c c o l o u r s w i t h f l a v o n o i d s . Photography o f t h e p l a t e s was done under long-wave u l t r a v i o l e t - 98 -l i g h t (366 nm) u s i n g Kodachrome 25 s l i d e f i l m (ASA 25) w i t h a Wratten 2E f i l t e r . P r i n t s made from the s l i d e s o b t a i n e d a r e shown i n P l a t e s 33 t o 42. R e s u l t s . A t o t a l o f more t h a n f o r t y f l a v o n o i d s were i s o l a t e d f r o m f i v e s p e c i e s o f H i e r a c i u m . More th a n h a l f o f t h e s e , most o f them f l a v o n e s , were i d e n t i f i e d . They a r e l i s t e d i n T a b l e IX, t o g e t h e r w i t h Rf v a l u e s and c o l o u r r e a c t i o n s . C o l o u r l e s s o r b l u e - f l u o r e s c i n g compounds were u s u a l l y d i s c a r d e d . However, one c o l o u r l e s s compound, which s l o w l y r e a c t e d w i t h the d i p h e n y l b o r a t e s p r a y t o g i v e a f l u o r e s c e n t r e d c o l o u r , was i s o l a t e d from H_. g r a c i l e . T h i s compound had a UV sp e c t r u m c l o s e l y r e s e m b l i n g t h a t • o f a f l a v a n o n e . F u r t h e r i n v e s t i g a t i o n o f the b l u e - f l u o r e s c i n g p o r t i o n o f the c r u d e e x t r a c t might y i e l d o t h e r f l a v o n o i d s o f i n t e r e s t . S t r u c t u r a l d e t e r m i n a t i o n s were t e n t a t i v e o r i n c o m p l e t e f o r f i v e o f t h e compounds l i s t e d . Compound 4 appear s t o be the y - l a c t o n e o f a p i g e n i n 7 - 0 - g - D - g l u c u r o n i d e . Upon t r e a t m e n t w i t h ammonium h y d r o x i d e i t was r a p i d l y c o n v e r t e d t o t h e g l u c u r o n i d e , and i t s u l t r a v i o l e t s p e c t r u m and p r o d u c t s o f h y d r o l y s i s were i d e n t i c a l w i t h t h o s e o f the l a t t e r compound. The i n f r a r e d s p e c t r u m ( s e e F i g u r e 19) was v e r y s i m i l a r t o t h a t o f a p i g e n i n 7-0-g-D-g l u c u r o n i d e , e x c e p t f o r a peak a t 1790 cm" 1 ( w i t h i n t he e x p e c t e d range f o r y - l a c t o n e s ) . A peak a t 1800 cm" 1 was r e p o r t e d by Wagner ejt al_ (1971) f o r the a c e t y l d e r i v a t i v e o f a p i g e n i n 7 - 0 - g l u c u r o n i c a c i d 3 , 6 - y - l a c t o n e . The 4 ' - 0 - g l u c u r o n i d e s l i s t e d i n T a b l e IX were i s o l a t e d i n d e r i v e d form T a b l e IX. Rf v a l u e s and c o l o u r r e a c t i o n s o f H i e r a c i u m f l a v o n o i d s . Rf v a l u e s X 100 C o l o u r s o f compounds i n UV l i g h t S o l v e n t s Compounds I I I I I I unsprayed w i t h d i p h e n y l b o r a t e 1. a p i g e n i n 7 63 6 p u r p l e green 2. ap 7 - 0 - 3 - D - g l u c o s i d e 36 32 16 p u r p l e green 3. ap 7 - 0 - 3 - D - g l u c u r o n i d e 2 2 19 p u r p l e g r e e n 4. ap 7 - 0 - g l u c u r o n o l a c t o n e 2 33 53 20 p u r p l e green 5. ap 7 - 0 - a r a b i n o s i d e 28 32 18 p u r p l e g r e e n 6. ap 7 - 0 - x y l o s y l g l u c o s i d e 57 16 23 p u r p l e green 7. ap 7 - 0 - a r a b i n o s y l g l u c o s i d e 57 16 23 p u r p l e g r e e n 8. ap 7 - 0 - r h a m n o s y l g l u c o s i d e 58 19 33 p u r p l e green 9. ap 4 ' - 0 - g l u c o s i d e 36 32 19 p u r p l e brown-green 10. ap 4 ' - 0 - g l u c u r o n i d e d e r i v . 2 29 62 30 p u r p l e brown-green 11. l u t e o l i n 5 42 5 purple-brown o r a n g e - y e l l o w 12. l u t 7 - 0 - 3 - D - g l u c o s i d e 33 16 8 purple-brown o r a n g e - y e l l o w 13. l u t 7 - 0 - 3 - D - g l u c u r o n i d e 1 1 8 purple-brown o r a n g e - y e l l o w "See page 96. i d e n t i f i c a t i o n t e n t a t i v e o r i n c o m p l e t e ; see d i s c u s s i o n i n t e x t . T a b l e IX. ( c o n t ' d ) Compounds Rf v a l u e s X 100 C o l o u r s o f compounds i n UV l i g h t I II I I I u n sprayed w i t h d i p h e n y l b o r a t e 14. l u t e o l i n 7 - 0 - a r a b i n o s i d e 25 16 6 purple-brown o r a n g e - y e l l o w 15. l u t 7 - 0 - x y l o s y l g l u c o s i d e 56 8 14 purple-brown o r a n g e - y e l l o w 16. l u t 7 - 0 - a r a b i n o s y l g l u c o s i d e 56 8 14 purple-brown o r a n g e - y e l l o w 17. l u t 7 - 0 - r h a m n o s y l g l u c o s i d e 56 11 18 purple-brown o r a n g e - y e l l o w 18. l u t 7 - 0 - t r i o s i d e 2 34 39 13 purple-brown o r a n g e - y e l l o w 19. l u t 4 ' - 0 - g l u c o s i d e 27 19 11 p u r p l e green 20. l u t 4 ' - 0 - g l u c u r o n i d e d e r i v . 2 20 47 15 p u r p l e green 21. l u t 4 ' - 0 - a r a b i n o s i d e 24 20 79 p u r p l e green 22. c h r y s o e r i o l 70 4 p u r p l e g r e e n 23. q u e r c e t i n 3 - 0 - g l u c o s i d e 28 15 32 purple-brown l i g h t orange 24 unknown g l u c o s i d e 2 9 9 4 dark brown b r i g h t y e l l o w - g r e e n 2 S e e f o o t n o t e on p r e v i o u s page. - 101 -o n l y , and p r o b a b l y have an a l i p h a t i c a c y l group on t h e s u g a r . The Rf v a l u e s o f t h e s e compounds on polyamide were much too h i g h f o r s i m p l e g l u c u r o n i d e s . The NMR sp e c t r u m o f the a p i g e n i n compound (as the t r i m e t h y l s i l y l d e r i v a t i v e , i n c a r b o n t e t r a c h l o r i d e ) showed two e x t r a p r o t o n s a t 6 = 3.8, but the n a t u r e o f t h e s e was not d e t e r m i n e d . Both o f t h e s e compounds, when t r e a t e d w i t h base, gave i n t e r m e d i a t e s w i t h Rf v a l u e s somewhat l i k e t h o s e o f a p i g e n i n and l u t e o l i n 7 - 0 - g l u c o s i d e s . In a d d i t i o n , both compounds t e s t e d n e u t r a l when s p r a y e d w i t h an a c i d - b a s e i n d i c a t o r ( a p i g e n i n and l u t e o l i n 7 - 0 - g l u c u r o n i d e s were a c i d i c ) . P o s s i b l y , both a c y l a t i o n and l a c t o n e f o r m a t i o n a r e i n v o l v e d . F i g u r e 19. I n f r a r e d s p e c t r a o f a p i g e n i n 7 - 0 - B - D - g l u c u r o n i d e (A) and i t s y - l a c t o n e ( B ) . ( P r e p a r e d as KBr p e l l e t s . ) 2 0 0 0 1 5 0 0 1 0 0 0 7 0 0 wavenumber, cm - 102 -The l u t e o l i n t r i o s i d e was t e n t a t i v e l y i d e n t i f i e d as l u t e o l i n 7-0-g l u c u r o n o s y l a r a b i n o s y l g l u c o s i d e . P a r t i a l h y d r o l y s i s gave two i n t e r m e d i a t e g l y c o s i d e s ; the f i r s t o f t h e s e co-chromatographed w i t h l u t e o l i n 7 - 0 - x y l o s y l -g l u c o s i d e ( x y l o s e and a r a b i n o s e behave v e r y s i m i l a r l y i n the s o l v e n t systems used here) and t h e second w i t h l u t e o l i n 7 - 0 - g l u c o s i d e . The l i n k a g e s between the s u g a r s were n o t d e t e r m i n e d . I t i s p r o b a b l e t h a t t h e g l u c u r o n i c a c i d i n t h i s t r i o s i d e i s e s t e r i f i e d , e i t h e r i n t e r n a l l y o r by an a d d i t i o n a l s u b s t i t u e n t , s i n c e t h e compound was o t h e r w i s e much t o o m o b i l e i n s o l v e n t I I . An unknown g l u c o s i d e ( t h e l a s t compound l i s t e d i n T a b l e IX) was i s o l a t e d from t h r e e o f the f i v e H i e r a c i u m s p e c i e s examined. The UV s p e c t r a l maxima i n methanol were 258, 2 6 6 ( s ) , 289 and 360. The compound has no v i c i n a l h y d r o x y l groups ( t h e aluminum c h l o r i d e s h i f t was a c i d - s t a b l e ) but t h e r e i s a t l e a s t one f r e e h y d r o x y l group on t h e B - r i n g , and p r o b a b l y an o c c u p i e d ( g l u c o s y l a t e d ? ) h y d r o x y l group i n t h e 7 - p o s i t i o n . I t h y d r o l y s e d r e a d i l y w i t h 8 - g l u c o s i d a s e , and t o t a l a c i d h y d r o l y s i s y i e l d e d g l u c o s e and an u n f a m i l i a r a g l y c o n e . Attempts t o o b t a i n an u l t r a v i o l e t o r NMR s p e c t r u m o f the a g l y c o n e were u n s u c c e s s f u l . D i s t r i b u t i o n o f the compounds among t h e f i v e s p e c i e s o f H i e r a c i u m i s shown i n T a b l e X. The s y s t e m a t i c i m p l i c a t i o n s o f the r e s u l t s a r e i n t e r e s t i n g . There i s a d e f i n i t e r e l a t i o n s h i p between m o r p h o l o g i c a l s i m i l a r i t y and c h e m i c a l s i m i l a r i t y . F i v e d i f f e r e n t a g l y c o n e t y p e s were i s o l a t e d . Of t h e s e , a p i g e n i n and T 3 o a g l y c o n e 7 - 0 - 3 - D - g l u c o s i d e 7 - 0 - 3 - D - g l u c u r o n i d e 7 - 0 - g l u c u r o n o l a c t o n e 7 - 0 - a r a b i n o s i d e 7 - 0 - x y l o s y l g l u c o s i de 7 - 0 - a r a b i n o s y l g l u c o s i d e 7 - 0 - r h a m n o s y l g l u c o s i de 4 ' - O - g l u c o s i d e 4 ' - O - g l u c u r o n i d e a g l y c o n e 7 - 0 - 3 - D - g l u c o s i d e 7 - 0 - 3 - D - g l u c u r o n i d e 7 - 0 - a r a b i n o s i d e 7 - 0 - x y l o s y l g l u c o s i d e 7 - 0 - a r a b i n o s y l g l u c o s i d e 7-0-rhamnosylgl u c o s i d e 7 - 0 - t r i o s i d e 4 ' - O - g l u c o s i d e 4 ' - O - g l u c u r o n i d e 4 ' - O - a r a b i n o s i d e c h r y s o e r i o l q u e r c e t i n 3 - 0 - g l u c o s i d e unknown g l u c o s i d e - eoL -- 104 -l u t e o l i n were found i n a l l f i v e s p e c i e s and a c c o u n t f o r e s s e n t i a l l y a l l o f t h e g l y c o s i d i c v a r i a t i o n . These two f l a v o n e s a r e common i n h i g h e r p l a n t s , e s p e c i a l l y i n the A s t e r a c e a e (Harborne 1967). C h r y s o e r i o l ( 3 1 - 0 - m e t h y l -l u t e o l i n ) appeared i n a l l t h e s p e c i e s e x c e p t H_. a l b i f l o r u m , but o n l y as the a g l y c o n e ( a l t h o u g h i t i s p r o b a b l e t h a t the g l u c o s i d e was p r e s e n t i n t r a c e amounts). The o n l y f l a v o n o l i d e n t i f i e d w i t h c e r t a i n t y was q u e r c e t i n , o c c u r r i n g i n H_. umbellatum as t h e 3 - 0 - g l u c o s i d e . The f i n a l a g l y c o n e t y p e , the unknown i s o l a t e d from JH_. umbel!atum, H_. c y n o g l o s s o i d e s and H_. a l b i f l o r u m , i s p r o b a b l y a f l a v o n o l j u d g i n g from t h e UV maxima, but i t s s t r u c t u r e was no t d e t e r m i n e d . The p a t t e r n s o f g l y c o s y l a t i o n f o u n d i n a p i g e n i n and l u t e o l i n a r e perhaps o f g r e a t e r i n t e r e s t . Four compounds, the 7- and 4 ' - 0 - g l u c o s i d e s o f a p i g e n i n and l u t e o l i n , were found i n a l l s p e c i e s . L u t e o l i n 7 - 0 - g l u c o s i d e , p r o b a b l y t h e commonest f l a v o n e g l y c o s i d e f o u n d i n h i g h e r p l a n t s , was t h e major compound i n e v e r y s p e c i e s examined. The o t h e r g l y c o s i d e s d i s p l a y e d a more s p e c i e s - s p e c i f i c d i s t r i b u t i o n . G l u c u r o n i d e s were f o u n d i n a l l t h e s p e c i e s examined, e x c e p t ( p e r h a p s ) H. a l b e r t i n u m , but t h e s u g a r was a t t a c h e d a t t h e 4 ' - p o s i t i o n i n H_. cyno- g l o s s o i d e s and a t t h e 7 - p o s i t i o n i n H_. umbellatum, H_. a l b i f l o r u m and H_. g r a c i l e . The l a t t e r t h r e e s p e c i e s a l s o y i e l d e d a p i g e n i n 7 - 0 - g l u c u r o n o l a c t o n e . However, s i n c e t h i s compound a p p e a r s t o be i n t e r c o n v e r t i b l e w i t h t h e g l u c u r o n i d e , i t may be an a r t i f a c t o f e x t r a c t i o n r a t h e r than t he p r o d u c t o f a p l a n t enzyme. - 105 -The 7- and 4 ' - 0 - a r a b i n o s i d e s o f l u t e o l i n , which a r e r e p o r t e d here f o r the f i r s t t i m e , and the 7 - 0 - a r a b i n o s i d e o f a p i g e n i n ( f o u n d p r e v i o u s l y i n C i c h o r i u m i n t y b u s , Dem'yanenko & D r a n i k 1973) were i s o l a t e d o n l y from H i e r a c i u m umbellatum. T h i s s p e c i e s was t h e o n l y one o f t h e f i v e i n which a s u g a r o t h e r than g l u c o s e ( o r g l u c u r o n i c a c i d , which i s v e r y s i m i l a r ) was found l i n k e d d i r e c t l y t o the f l a v o n e . T h r e e d i f f e r e n t k i n d s o f b i o s i d e s and one t r i o s i d e were i d e n t i f i e d . F l a v o n e r h a m n o g l u c o s i d e s a r e f a i r l y common (se e Harborne 1967), but t h e o t h e r two b i o s i d e . t y p e s t h a t were found i n H i e r a c i u m a r e r a r e . L u t e o l i n 7 - 0 - x y l -o s y l g l u c o s i d e has p r e v i o u s l y been r e p o r t e d from S a l i x c a e s i a (Rabate* 1938) and S.. r e pens (Thieme 1968), and l u t e o l i n 7 - 0 - a r a b i n o s y l g l u c o s i d e o n l y f r o m Cyperus l o n g u s (Harborne 1971). The c o r r e s p o n d i n g a p i g e n i n g l y c o s i d e s have no t p r e v i o u s l y been found. H i e r a c i u m a l b e r t i n u m and H_. c y n o g l o s s o i d e s c o n t a i n e d o n l y t h e x y l o s y l g l u c o s i d e s . These two s p e c i e s a r e c h e m i c a l l y v e r y s i m i l a r . Only t h e r h a m n o g l u c o s i d e s were found i n JH_. a l b i f l o r u m . I n t e r e s t i n g l y , H_. g r a c i l e (which on the b a s i s o f c y t o l o g i c a l e v i d e n c e i s c l o s e l y r e l a t e d t o both H_. a l b i f l o r u m and the members o f the H^ . s c o u l e r i complex) c o n t a i n e d both r h a m n o s y l . g l u c d s i d e s and a x y l o s y l g l u c o s i d e , as w e l l as a unique l u t e o l i n t r i o s i d e . H i e r a c i u m umbellatum, a l t h o u g h i t p o s s e s s e s a number o f compounds i n common w i t h the o t h e r s p e c i e s , was t h e o n l y s p e c i e s from which a r a b i n o s y l g l u c o s i d e s were i s o l a t e d . The r e l a t i o n s h i p between t h e genome and i t s e x p r e s s i o n i s more d i r e c t i n t h e c a s e o f c h e m i c a l i n f o r m a t i o n than i t i s f o r many o t h e r t y p e s o f s y s t e m a t i c e v i d e n c e . In morphology, f o r example, the a c t u a l number o f genes - 106 -r e g u l a t i n g a g i v e n c h a r a c t e r ( l e a f shape, pubescence, b r a n c h i n g p a t t e r n ) i s seldom known. Chemical d a t a u s u a l l y r e p r e s e n t a r e l a t i v e l y s m a l l p o r t i o n o f the genome; however, i f s u f f i c i e n t i n f o r m a t i o n on b i o s y n t h e t i c pathways i s g a t h e r e d , i t s h o u l d be p o s s i b l e t o d e t e r m i n e t he number o f d i f f e r e n t enzymes r e q u i r e d f o r the s y n t h e s i s o f a g i v e n m e t a b o l i c p r o d u c t (and hence to a r r i v e a t an e s t i m a t e o f t h e number o f genes i n v o l v e d ) . Comparisons between two t a x a can then be made i n :terms o f , t h e number o f t h e s e genes t h a t they have i n common. In p r a c t i c e t he a v a i l a b l e i n f o r m a t i o n on d i f f e r e n c e s i n b i o s y n t h e t i c r o u t e s , enzyme s p e c i f i c i t i e s e t c e t e r a i s seldom complete. However, knowledge o f how a group o f compounds i s s y n t h e s i z e d c l e a r l y makes c o m p a r a t i v e c h e m i c a l d a t a more t a x o n o m i c a l l y m e a n i n g f u l . The b i o s y n t h e s i s o f f l a v o n o i d s has been s t u d i e d by a number o f a u t h o r s ( G r i s e b a c h 1965 and 1968, Wong & G r i s e b a c h 1969, E n d r e s s 1972, G r i s e b a c h 1973, Roux & F e r r e i r a 1974). The p r o b a b l e b i o s y n t h e t i c pathway f o r t h e a g l y c o n e s f o u n d i n H i e r a c i u m i s shown i n F i g u r e 20. H y d r o x y l a t i o n a t t h e 3 - p o s i t i o n o c c u r s a t t h e l e v e l o f t h e f l a v a n o n e / c h a l c o n e ; 3 ' - h y d r o x y l a t i o n o c c u r s a f t e r t h e f l a v o n e o r f l a v o n o l i s formed, a t l e a s t i n some p l a n t s ( G r i s e b a c h 1973). The f i n a l s t e p i s 0 - m e t h y l a t i o n . Sugars a r e added t o the f l a v o n o i d a g l y c o n e one a t a t i m e , from a n u c l e o t i d e c a r r i e r ( B a r b e r 1962). R e l a t i v e l y l i t t l e i s known about t h e number o f enzymes r e q u i r e d t o produce a group o f f l a v o n o i d s g l y c o s y l a t e d by d i f f e r e n t s u g a r s and a t d i f f e r e n t p o s i t i o n s . However, S u t t e r & G r i s e b a c h (1973) i s o l a t e d a g l u c o s y l t r a n s f e r a s e from p a r s l e y which was s p e c i f i c f o r the 3 - p o s i t i o n . I t c a t a l y z e d the t r a n s f e r w i t h a number o f d i f f e r e n t F i g u r e 20. The p r o b a b l e b i o s y n t h e s i s o f the f l a v o n o i d a g l y c o n e s found i n H i e r a c i u m . o H O O HO 0 HO 0 q u e r c e t i n - 108 -f l a v o n o l s o r f l a v o n o l g l y c o s i d e s ( b u t n o t w i t h f l a v a n o n o l s ) . G r i s e b a c h (1973) r e p o r t e d an enzyme s p e c i f i c f o r the t r a n s f e r o f a p i o s e t o t h e s u g a r m o i e t y o f f l a v o n e 7 - 0 - g l u c o s i d e s o r g l u c u r o n i d e s . I t was n o t f u n c t i o n a l w i t h f l a v o n o l 3 - 0 - g l u c o s i d e s . S i m i l a r l y , van B r e d e r o d e ejt al_ (1974) found two enzymes t h a t were s p e c i f i c f o r the t r a n s f e r o f g l u c o s e and x y l o s e , r e s p e c t i v e l y , t o t h e 7 - p o s i t i o n o f i s o v i t e x i n . The two enzymes competed f o r the f l a v o n e s u b s t r a t e . G e n e t i c s t u d i e s showed t h a t a l t e r a t i o n o f t h e b e h a v i o u r o f a s i n g l e gene ( f r o m codominance t o r e c e s s i v e n e s s ) r e s u l t e d i n p l a n t s t h a t p roduced one enzyme o r t h e o t h e r , but n o t both. A l t h o u g h t h e p o s s i b i l i t y o f b i o s y n t h e t i c d i f f e r e n c e s between one p l a n t group and the n e x t must be kept i n mind, t h e s e s t u d i e s g i v e c l u e s t o the p o s s i b l e number o f enzymes i n v o l v e d i n t h e g l y c o s y l a t i o n o f H i e r a c i u m f l a v o n o i d s . C o r r e s p o n d i n g p a i r s o f a p i g e n i n and l u t e o l i n g l y c o s i d e s ( e . g . , the 7-0-gl u c o s i d e s ) a r e p r o b a b l y p r o d u c t s o f t h e same enzyme. The b i o s i d e s a r e p r oduced by t r a n s f e r a s e s a c t i n g s p e c i f i c a l l y on g l u c o s y l a t e d f l a v o n e s . I f t h i s were no t the c a s e , rhamnosides o r x y l o s i d e s might have been e x p e c t e d i n the H i e r a c i u m s p e c i e s t h a t produced t h o s e s u g a r s . I t i s p o s s i b l e t h e r e a r e s i m p l y two o r t h r e e enzymes o f broad s p e c i f i c i t y , but i t , i s more l i k e l y t h a t t h e r e a r e d i f f e r e n t enzymes f o r t h e d i f f e r e n t p o s i t i o n s o f a t t a c h m e n t (3, 7 and 4') and f o r each o f t h e v a r i o u s s u g a r s . A p o s s i b l e scheme f o r the g l y c o s y l a t i o n o f the f l a v o n e s , a p i g e n i n and l u t e o l i n , i n H i e r a c i u m i s g i v e n i n F i g u r e 21. The p a t t e r n s t h a t were f o u n d i n each s p e c i e s a r e i n d i c a t e d , so t h a t an e s t i m a t e o f the enzyme d i f f e r e n c e s between t h e s p e c i e s can be made. F i g u r e 21. P o s s i b l e g l y c o s y l a t i n g enzymes i n the d i f f e r e n t s p e c i e s o f H i e r a c i u m . 7 - 0 - g l u c u r o n o s y l -a r a b i n o s y l g l u c o s i d e 4 ' - 0 - a r a b i n o s ' H_. c y n o g l o s s o i d e s H_. a l b i f l o r u m H_. g r a c i l e - no -The d i agram shows t h a t H i e r a c i u m a l b e r t i n u m and H_. c y n o g l o s s o i d e s a r e v e r y much a l i k e , h a v i n g t h r e e enzyme s t e p s i n common and d i f f e r i n g i n o n l y one. Even t h i s d i f f e r e n c e may n o t be a g e nuine s p e c i e s d i f f e r e n c e , s i n c e the 4 ' - 0 - g l u c u r o n i d e s i n H_. c y n o g l o s s o i d e s were minor compounds, and H_. a l b e r t i n u m d i d c o n t a i n t r a c e amounts o f a compound w i t h t h e r i g h t Rf v a l u e s . Q u a n t a t i v e v a r i a t i o n i n minor f l a v o n o i d s can sometimes g i v e m i s l e a d i n g r e s u l t s . H i e r a c i u m a l b i f l o r u m i s c a p a b l e o f two b i o s y n t h e t i c s t e p s t h a t a r e l a c k i n g i n s p e c i e s o f t h e JH_. s c o u l e r i complex, but i t l a c k s t h e a b i l i t y t o produce x y l o s y l g l u c o s i d e s and 4 ' - O - g l u c u r o n i d e s . A l t h o u g h t h i s s p e c i e s h y b r i d i z e s w i t h the s p e c i e s o f the JH. s c o u l e r i complex, c h e m i c a l l y i t i s q u i t e d i s t i n c t . The c h e m i s t r y o f h y b r i d s between c h e m i c a l l y d i f f e r i n g p a r e n t s i s u s u a l l y a d d i t i v e ( A l s t o n & T u r n e r 1959 & 1963, A l s t o n e t i l 1965, O r n d u f f e t a l ^ 1973). H y b r i d s between t h e s e two groups s h o u l d t h e r e f o r e be r e a d i l y d i s t i n g u i s h a b l e by t h e type o f b i o s i d e s t h e y c o n t a i n . I t might a l s o be p o s s i b l e t o d e t e c t i n t r o g r e s s i o n by t h i s means, but x y l o s y l g l u c o s i d e s and r h a m n o s y l g l u c o s i d e s a r e not r e a d i l y s e p a r a b l e on a t w o - d i m e n s i o n a l chromato-gram. ( T h i s i s m entioned f u r t h e r on page 119.) In t h i s s t u d y , H i e r a c i u m  s c o u l e r i was n o t one o f t h e s p e c i e s s u b j e c t e d t o d e t a i l e d c h e m i c a l a n a l y s i s , but two compounds (an a p i g e n i n d e r i v a t i v e and a l u t e o l i n d e r i v a t i v e ) h a v i n g the e x p e c t e d Rfs f o r b i o s i d e s were i s o l a t e d f r o m the c r u d e e x t r a c t . One o f t h e s e y i e l d e d g l u c o s e and x y l o s e on a c i d h y d r o l y s i s . I t a p p e a r s t h a t the c h e m i s t r y o f JJ_. s c o u l e r i resembles t h a t o f t h e o t h e r two s p e c i e s o f t h i s group. - I l l -H i e r a c i u m g r a c i l e , i f the p o s t u l a t e d s t r u c t u r e f o r i t s t r i o s i d e i s c o r r e c t , s h o u l d be a b l e t o s y n t h e s i z e a l l t h r e e o f the b i o s i d e s shown i n F i g u r e 21, a l t h o u g h no a r a b i n o s y l g l u c o s i d e s were found i n t h i s p l a n t . I f t h i s i s s o , i t i s c a p a b l e o f t h r e e b i o s y n t h e t i c s t e p s not found i n a l b i f l o r u m and f o u r s t e p s not f o u n d i n t h e s p e c i e s o f the H_. s c o u l e r i complex. The two l a t t e r groups c o n t a i n e d no compounds not fou n d i n H_. g r a c i l e , e x c e p t f o r t h e 4 ' - 0 - g l u c u r o n i d e s i n H_. c y n o g l o s s o i d e s . H y b r i d s between H_. g r a c i l e and any o f t h e s e s p e c i e s s h o u l d c h e m i c a l l y resemble H^ . g r a c i l e . H i e r a c i u m umbellatum, a l t h o u g h i t b e l o n g s t o a s e p a r a t e subgenus, d i f f e r s no more g r e a t l y f r o m t h e remainder o f the s p e c i e s than t h e y do from one a n o t h e r . I t i s d i s t i n c t i n b e i n g a b l e t o s y n t h e s i z e the 7- and 4'-0-a r a b i n o s i d e s . A p a r t from t h i s , a l l t h e compounds found i n t h i s p l a n t were a l s o p r e s e n t i n a t l e a s t one o f t h e o t h e r s p e c i e s . A l l t h e b i o s y n t h e t i c c a p a b i l i t i e s o f H_. a l b i f l o r u m a r e a l s o p o s s e s s e d by H_. umbel l a t u m , a l t h o u g h H_. g r a c i l e and the s p e c i e s o f t h e H_. s c o u l e r i complex each have a t l e a s t one e n z y m a t i c s t e p n o t found i n t h i s s p e c i e s . Such a s m a l l number o f genes i s i n v o l v e d i n t h e i n t e r c o n v e r s i o n o f t h e s e c l o s e l y r e l a t e d f l a v o n e g l y c o s i d e s , however, t h a t i t i s m i s l e a d i n g t o draw taxonomic c o n c l u s i o n s about d i f f e r e n t subgenera s o l e l y on t h e b a s i s o f t h e d a t a p r e s e n t e d h e r e . I d e a l l y , many o t h e r H i e r a c i u m s p e c i e s s h o u l d be examined, as w e l l as a much l a r g e r number o f c h e m i c a l c h a r a c t e r s . In any c a s e , s i n c e t h e r e i s much s t i l l t o be l e a r n e d about f l a v o n o i d b i o s y n t h e s i s , the scheme p r e s e n t e d i n F i g u r e 21 i s n e c e s s a r i l y t e n t a t i v e . D i f f e r e n c e s i n c h e m i c a l c o m p o s i t i o n may r e s u l t from d i f f e r e n c e s i n t h e - 112 -a v a i l a b i l i t y o f s u b s t r a t e r a t h e r than t h e p r e s e n c e o r absence o f a p a r t i c u l a r enzyme. A l s o s l i g h t q u a n t i t a t i v e d i f f e r e n c e s i n minor compounds may appear as q u a l i t a t i v e d i f f e r e n c e s , when t h e amounts o f f l a v o n o i d a r e near t h e l i m i t s o f d e t e c t i o n . Some i n f o r m a t i o n on t h e H i e r a c i u m s p e c i e s t h a t were n o t a n a l y z e d i n d e t a i l was o b t a i n e d from t h e t w o - d i m e n s i o n a l chromatograms, phot o g r a p h s o f which a r e shown i n P l a t e s 33 t o 42. In the l i n e drawings accompanying each photograph t h e s p o t s have been numbered. The numbers c o r r e s p o n d t o t h o s e o f t h e compounds l i s t e d i n T a b l e V I I I , and i n d i c a t e t h e i d e n t i t y o r p r o b a b l e i d e n t i t y o f each s p o t . C o l o u r r e s p o n s e s t o d i p h e n y l b o r a t e a r e a l s o i n d i c a t e d . The drawings were o b t a i n e d by making t r a c i n g s o f t h e o r i g i n a l t h i n - l a y e r chromatograms, and some o f t h e compounds shown a r e n o t v i s i b l e i n t h e c o r r e s p o n d i n g p h o t o g r a p h s . T h i s i s due t o the l a c k o f s e n s i t i v i t y o f the p h o t o g r a p h i c f i l m t o c o l o u r s o f low i n t e n s i t y . I t can be seen t h a t H_. s c o u l e r i has a f l a v o n o i d a r r a y s i m i l a r t o t h a t o f t h e o t h e r s p e c i e s o f t h e complex; note t h e absence o f 7 - 0 - g l u c u r o m l d e s . A number o f t h e p h o t o g r a p h s show s p o t s t h a t were no t d e t e c t e d i n t h e mass c o l l e c t i o n s . These may i n d i c a t e t h a t the r e l a t i o n s h i p s between some o f t h e s p e c i e s a r e c l o s e r than T a b l e X. might suggest.... The p hotograph o f t h e H_. a l b i f l o r u m chromatogram, f o r example, c o n t a i n s a y e l l o w s p o t which c l o s e l y r e s embles ( i n c o l o u r and Rf) the t r i o s i d e i n H_. g r a c i l e . I n t e r e s t i n g l y , the t w o - d i m e n s i o n a l map o f H_. t r i s t e d i f f e r s c o n s i d e r a b l y from t h a t o f H_. g r a c i l e . The b i o s i d e s a r e s c a r c e l y v i s i b l e , and the l u t e o l i n t r i o s i d e o f H. g r a c i l e a ppears t o be l a c k i n g i n HL t r i s t e . C h r y s o e r i o l i s a b s e n t , and t h e r e a r e - 113 -P l a t e 33. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m umbellatum. The s p o t s o u t l i n e by d o t t e d l i n e s a r e n o n - f l a v o n o i d p h e n o l i c compounds. P l a t e 34. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m a l b e r t i n u m . - 114 -A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m c y n o g l o s s o i d e s . A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m s c o u l e r i . P l a t e 38. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m t r i s t e . P l a t e 40. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m g r a c i l e X H_. a l b i f l o r u m . - 117 -1,1 i P l a t e 41. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m g r a c i l e X c y n o g l o s s o i d e s . P l a t e 42. A t w o - d i m e n s i o n a l chromatogram o f H i e r a c i u m a l b i f l o r u m X H. s c o u l e r i . - 118 -two compounds a t the p o s i t i o n o f l u t e o l i n 7 - 0 - g l u c o s i d e and an e x t r a a g l y c o n e s p o t n e a r a p i g e n i n . The d i f f e r e n c e s a r e q u i t e marked. However, t h e map f o r H_. t r i s t e was p r e p a r e d from d r i e d h e r b a r i u m m a t e r i a l c o l l e c t e d i n 1962, and i t i s p o s s i b l e t h a t t h e f l a v o n o i d s i n t h e sample d e t e r i o r a t e d o v e r t h i s l o n g p e r i o d . No e f f o r t was made d u r i n g t h i s s t u d y t o a s s e s s i n t r a s p e c i f i c v a r i a b i l i t y i n c h e m i c a l c o m p o s i t i o n . Some o f the e x t r a c t s chromatographed f o r the two-d i m e n s i o n a l maps were t a k e n f r o m s i n g l e p l a n t s , however ( s e e T a b l e V I I I ) and p r o b a b l y some o f t h e s p o t s a r e not r e p r e s e n t a t i v e o f the s p e c i e s . The map o f \\_. umbel 1 atum c o n t a i n s a t l e a s t two a g l y c o n e s t h a t were no t d e t e c t e d i n t h e mass c o l l e c t i o n , and H_. c y n o g l o s s o i d e s shows two a d d i t i o n a l y e l l o w -f l u o r e s c i n g g l y c o s i d e s . Some o f t h i s c h e m i c a l v a r i a b i l i t y may be due t o f a c t o r s o t h e r than g e n e t i c d i f f e r e n c e s between i n d i v i d u a l s . T a y l o r (1971) found s e a s o n a l v a r i a t i o n i n t h e f l a v o n o i d s o f T i a r e l l a , and A s k e r & F r o s t (1972) found t h a t the f l a v o n o i d s o f P o t e n t i l l a v a r y w i t h p l a n t age. Parks e t al_ (1972) grew pure i n b r e d l i n e s o f f o u r Gossypium s p e c i e s i n d i f f e r e n t e n v i r o n m e n t s , and f o u n d c o r r e s p o n d i n g d i f f e r e n c e s i n t h e f l a v o n o i d p a t t e r n ( e s p e c i a l l y i n t h e l e a v e s ) . Q u a n t i t a t i v e d i f f e r e n c e s i n f l a v o n o i d s ( a n t h o -c y a n i n s i n p a r t i c u l a r ) a r e known t o r e s u l t from d i f f e r e n c e s i n a v a i l a b i l i t y o f l i g h t ( H a r b o r n e 1967), and a b i o c h e m i c a l b a s i s f o r t h i s has been e s t a b l i s h e d (Wellmann 1975). A l l m a t e r i a l used i n t h e p r e s e n t s t u d y was c o l l e c t e d i n f l o w e r and a t s i m i l a r s t a g e s o f development, and c o l l e c t i o n p r o c e d u r e s were s t a n d a r d i z e d as much as p o s s i b l e . S i n c e t h e p l a n t specimens were o b t a i n e d i n t h e f i e l d , however, some d i f f e r e n c e s i n e n v i r o n m e n t were u n a v o i d a b l e . - 119 -The i n t e r s p e c i f i c h y b r i d s ( P l a t e s 40 t o 42) appear t o combine the f l a v o n o i d a r r a y s o f t h e i r p a r e n t s p e c i e s . In any c a s e , t h e y c o n t a i n l a r g e r numbers o f compounds. A l a r g e y e l l o w s p o t i s v i s i b l e i n the two h y b r i d s i n v o l v i n g \±. g r a c i l e ( P l a t e s 40 and 4 1 ) , and r e sembles an a g l y c o n e o f s i m i l a r Rf i n t r i s t e . ( T h i s s u g g e s t s t h a t some o f t h e a p p a r e n t d i f f e r e n c e s between H_. t r i s t e and H_. g r a c i l e may be due t o i n t r a s p e c i f i c v a r i a t i o n between p o p u l a t i o n s , r a t h e r than s p e c i e s d i f f e r e n c e s . ) These two h y b r i d s each c o n t a i n a t l e a s t f o u r o t h e r a g l y c o n e s p o t s , a l a r g e r number th a n i s found i n any o f the t h r e e p a r e n t s p e c i e s . The h y b r i d between H_. a l b i f l o r u m and H_. s c o u l e r i c o n t a i n s o n l y t h r e e a g l y c o n e s , but exceeds both i t s p a r e n t s i n the number o f g l y c o s i d e s . The d i f f e r e n t b i o s i d d s t h a t would be e x p e c t e d i n each o f t h e s e h y b r i d s a r e u n f o r t u n a t e l y n o t d i s t i n g u i s h a b l e by Rf v a l u e s . S i m i l a r compounds can seldom be i d e n t i f i e d w i t h c e r t a i n t y from two-d i m e n s i o n a l chromatograms, s i n c e Rfs a r e a f f e c t e d by t e m p e r a t u r e , s a t u r a t i o n o f the c h r o m a t o g r a p h i c chamber, amounts o f compound p r e s e n t , and v a r i o u s o t h e r f a c t o r s q u i t e u n r e l a t e d t o s p e c i e s d i f f e r e n c e s . However, some u s e f u l c omparisons can be made from t h e p l a t e s i l l u s t r a t e d h e r e , and t e n t a t i v e c o n c l u s i o n s can be drawn which c o u l d then be c o n f i r m e d by more d e t a i l e d work. The r e s u l t s p r e s e n t e d h e r e , w h i l e t h e y a r e o f g r e a t e s t v a l u e i n d i s t i n g u i s h i n g between c l o s e l y r e l a t e d s p e c i e s , may a l s o be u s e f u l a t h i g h e r taxonomic l e v e l s . A comparison w i t h d a t a p u b l i s h e d f o r o t h e r genera and s p e c i e s i n the t r i b e C i c h o r i e a e may g i v e an i n d i c a t i o n o f t h e p o s i t i o n o f H i e r a c i u m w i t h i n the t r i b e . A c c o r d i n g t o S t e b b i n s (1953) t h e C i c h o r i e a e c o n s i s t s o f 64 g e n e r a , grouped i n t o e i g h t s u b t r i b e s . The f l a v o n o i d s have been i n v e s t i g a t e d i n s i x o t h e r genera b e s i d e s H i e r a c i u m . C i c h o r i u m i n t y b u s , the - 120 -common c h i c o r y , c o n t a i n s t h e f o l l o w i n g f l a v o n o i d s (Dem'yanenko & D r a n i k 1973): a p i g e n i n , a p i g e n i n 7 - 0 - L - a r a b i n o s i d e , l u t e o l i n 7 - 0 - 3 - D - g l u c u r o n i d e , q u e r c e t i n 3-0-rhamnoside and q u e r c e t i n 3 - 0 - g a l a c t o s i d e . Woeldecke & Herrmann (1974) i s o l a t e d t h r e e kaempferol d e r i v a t i v e s , one o f them a c y l a t e d , from C. e n d i v i a ( e n d i v e ) . P r o l i a c e t aj_ (1973, 1974) i n v e s t i g a t e d Catananche c a e r u l e a , a n o t h e r member o f t h e s u b t r i b e C i c h o r i n a e , and found l u t e o l i n 7 - 0 - g l u c o s i d e , l u t e o l i n 7 - 0 - r h a m n o s y l g l u c o s i d e , l u t e o l i n 7 - 0 - d i g l u c o s i d e , and f o u r f l a v o n e C - g l y c o s i d e s . F i v e North American s p e c i e s o f t h e genus Tragopogon ( s u b t r i b e S c o r z o n e r i n a e ) have been i n v e s t i g a t e d i n some d e t a i l . A p i g e n i n , l u t e o l i n , l u t e o l i n 7 - 0 - 3 - D - g l u c o s i d e , q u e r c e t i n 3 - 0 - 3 - D - g l u c o s i d e , and e l e v e n C - g l y c o -f l a v o n e s based on a p i g e n i n o r l u t e o l i n were i s o l a t e d (Kroschewsky e t a l 1969). T h i s a r r a y o f f l a v o n o i d s was found u s e f u l i n i d e n t i f y i n g both s p e c i e s and h y b r i d s ( B e l z e r e t a l 1971). Nakaoki & M o r i t a (1960) have r e p o r t e d l u t e o l i n 7 - 0 - g l u c o s i d e from L a c t u c a r e p e n s , and Woeldecke & Herrmann (1974) i s o l a t e d l u t e o l i n 7-0-g l u c u r o n i d e , q u e r c e t i n 3 - 0 - g l u c u r o n i d e , q u e r c e t i n 3 - 0 - g l u c o s i d e and q u e r c e t i n 3 - 0 - m a l o n y l - 3 - D f ) g l u c o s i d e from L_. s a t i v a ( c u l t i v a t e d l e t t u c e ) . A p i g e n i n and l u t e o l i n 7 - 0 - g l u c o s i d e s have been found i n Taraxacum o f f i c i n a l e (Horhammer & Wagner 1962), and Sonchus a r v e n s i s c o n t a i n s l u t e o l i n and l u t e o l i n 7-0-g l u c o s i d e (Bondarenko e t al_ 1973, 1974). These l a s t t h r e e genera a r e o f p a r t i c u l a r i n t e r e s t , as t h e y a r e i n c l u d e d w i t h H i e r a c i u m i n the s u b t r i b e C r e p i d i n a e . - 121 -M o r p h o l o g i c a l l y , t h e C i c h o r i e a e i s a w e l l - d e f i n e d n a t u r a l group w i t h i n the A s t e r a c e a e . The c o n s i s t e n t o c c u r r e n c e o f f l a v o n e s as t h e major f l a v o n o i d s adds t o morphology t h e s u p p o r t o f c h e m i c a l e v i d e n c e . A l s o o f i n t e r e s t i s t h e c h e m i c a l s i m i l a r i t y o f t h e s p e c i e s which have so f a r been examined from the s u b t r i b e C r e p i d i n a e . Common g l u c o s i d e s and g l u c u r o n i d e s and a c y l a t e d d e r i v a t i v e s have been f o u n d , but no C - g l y c o s y l a t e d f l a v o n o i d s ( i n c o n t r a s t t o t h o s e o f the o t h e r two s u b t r i b e s t h a t have been i n v e s t i g a t e d ) . However, many more t a x a must be sampled b e f o r e f u r t h e r c o n c l u s i o n s can be drawn. - 122 -VI. DISCUSSION The r e s u l t s p r e s e n t e d i n t h e p r e c e d i n g c h a p t e r s a r e o f i n t e r e s t from two v i e w p o i n t s . F i r s t , t he d a t a a c c u m u l a t e d f o r each s p e c i e s can be d i s c u s s e d i n terms o f t h e a d a p t a t i o n s o f t h e s p e c i e s t o the e n v i r o n m e n t i n which i t o c c u r s . S e c o n d l y , c o n c l u s i o n s can be drawn c o n c e r n i n g the r e l a t i o n s h i p s between s p e c i e s , and a taxonomic t r e a t m e n t proposed on the b a s i s o f t h e s e c o n c l u s i o n s . T h e o r e t i c a l C o n s i d e r a t i o n s . The i n f o r m a t i o n d i s c u s s e d here i s o f g r e a t e s t taxonomic v a l u e a t t h e l e v e l o f the s p e c i e s and below. A b r i e f d i s c u s s i o n o f some r e l e v a n t c o n c e p t s i s g i v e n h e r e . The term " s p e c i e s " has been d i s c u s s e d , w i t h l i t t l e agreement, by num-erous b o t a n i s t s s i n c e t h e time o f L i n n a e u s . As C r o n q u i s t (1968) s t a t e s , an e x a c t d e f i n i t i o n o f t h i s c o n c e p t i s p r o b a b l y n o t p o s s i b l e . He d e s c r i b e s a s p e c i e s as "the s m a l l e s t p o p u l a t i o n which i s p e r m a n e n t l y ( i n terms o f human time) d i s t i n c t and d i s t i n g u i s h a b l e from a l l o t h e r s " . What c o n s t i t u t e s a d i s t i n c t d i f f e r e n c e i s n e c e s s a r i l y a m a t t e r o f o p i n i o n . Most a u t h o r s a r e agreed t h a t a r e c o g n i z a b l e amount o f m o r p h o l o g i c a l d i s c o n t i n u i t y s h o u l d e x i s t between d i f f e r e n t s p e c i e s , and s u g g e s t i o n s have been made f o r minimum r e q u i r e m e n t s i n numbers o f c o r r e l a t e d d i f f e r e n c e s . Hedberg (1958) proposed t h a t s p e c i e s s h o u l d d i f f e r by a t l e a s t two c o r r e l a t e d , i n d e p e n d e n t , d i s c o n -t i n u o u s l y v a r y i n g c h a r a c t e r s ; Sneath (1958) s u g g e s t e d a t l e a s t f i v e c o r r e l a t e d c h a r a c t e r d i f f e r e n c e s . - 123 -The view t h a t d i f f e r e n t s p e c i e s s h o u l d be r e p r o d u c t i v e l y i s o l a t e d (and c o n v e r s e l y , t h a t i n t e r s t e r i l e p o p u l a t i o n s s h o u l d be t r e a t e d as b e l o n g i n g t o s e p a r a t e s p e c i e s ) i s no l o n g e r w i d e l y h e l d ( V a l e n t i n e & Love 1958, Lewis 1957, R a d f o r d e t al_ 1974), a l t h o u g h c r o s s a b i l i t y s t u d i e s a r e a v a l u a b l e s o u r c e o f a d d i t i o n a l i n f o r m a t i o n on which t o base taxonomic c o n c l u s i o n s . Mosquin (1966b) has p o i n t e d out t h a t r e p r o d u c t i v e i s o l a t i o n and m o r p h o l o g i c a l d i s c o n t i n u i t y a r e v e r y f r e q u e n t l y not a s s o c i a t e d i n p l a n t s p e c i e s . T h i s underl.ines t h e f a c t t h a t no taxonomic r u l e s can be f o r m u l a t e d t h a t w i l l be r e l i a b l e i n a l l s i t u a t i o n s . Each taxonomic problem must be c o n s i d e r e d s e p a r a t e l y , w i t h due r e g a r d b e i n g g i v e n t o the weight o f t r a d i t i o n , and t o the n e c e s s i t y o f p r o d u c i n g a u s a b l e , p r a c t i c a l t r e a t m e n t . In a d d i t i o n , i f a c l a s s i f i c a t i o n i s t o be u s e f u l and s t a b l e , s i m i l a r d e g r e e s o f d i f f e r e n c e i n d i f f e r e n t groups s h o u l d r e c e i v e s i m i l a r taxonomic t r e a t m e n t . The S p e c i e s o f H i e r a c i u m : B i o l o g y and I n t e r r e l a t i o n s h i p s . For t h e purposes o f t h i s d i s c u s s i o n t h e s e hawkweeds a r e grouped under f o u r h e a d i n g s , c o r r e s p o n d i n g t o the f o u r n a t u r a l s p e c i e s g r o u p s . The d i f f e r e n t groups each d i s p l a y s p e c i f i c a d a p t a t i o n s t o t h e i r p a r t i c u l a r h a b i t a t . (1) The North American H i e r a c i u m umbellatum complex. The p l a n t s o f t h i s group a r e f r e q u e n t l y e n c o u n t e r e d i n s u c c e s s i o n a l o r d i s t u r b e d h a b i t a t s , f o r example a l o n g road c l e a r a n c e s . The group i s m o r p h o l o g i c a l l y q u i t e h e t e r o g e n e o u s , a t l e a s t i n t h o s e c h a r a c t e r s t h a t were measured. V a r i a t i o n i n morphology i s c l i n a l and t h e r e a p p e a r s t o be no c o r r e l a t i o n w i t h e n v i r o n m e n t a l f a c t o r s . One c h a r a c t e r t h a t v a r i e s q u i t e - 124 -n o t i c e a b l y i s l e a f a r e a (as r e f l e c t e d by l e a f l e n g t h - t o - w i d t h r a t i o ) . A r e d u c t i o n i n l e a f a r e a i s p r o b a b l y advantageous under c o n d i t i o n s o f h i g h t e m p e r a t u r e o r v e r y low h u m i d i t y , when i t c u t s down on l o s s o f water by t r a n s p i r a t i o n (Daubenmire 1959). However, t h e r e i s no e v i d e n c e t h a t i t s e r v e s t h i s f u n c t i o n i n H i e r a c i u m umbellatum. C y t o l o g i c a l l y , H_. umbellatum has now been w e l l i n v e s t i g a t e d i n B r i t i s h C olumbia, and H_. canadense has been sampled f r o m s e v e r a l l o c a t i o n s i n the e a s t ( G u s t a f s o n 1933). These p l a n t s appear t o be agamospermous and t r i p l o i d t h r o u g h o u t t h e i r range on t h i s c o n t i n e n t . As m i ght be e x p e c t e d , m e i o s i s i s c o n s i s t e n t l y i r r e g u l a r i n the p o l l e n m e i o s p o r o c y t e s , and p o l l e n v i a b i l i t y i s v e r y low. The o c c u r r e n c e o f both a p o m i x i s and p o l y p l o i d y i n t h i s complex i s i n t e r e s t i n g , s i n c e t h e a s s o c i a t i o n o f t h e s e two phenomena has been o b s e r v e d i n many genera o f f l o w e r i n g p l a n t s ( S t e b b i n s 1950, 1970). A p o s s i b l e r e a s o n f o r t h i s c o - o c c u r r e n c e , a c c o r d i n g t o G u s t a f s s o n ( 1 9 4 7 ) , i s t h a t p o l y p l o i d y may s t r e n g t h e n t h e a c t i o n o f a p o m i x i s - i n d u c i n g genes t h a t a r e l a t e n t i n t h e d i p l o i d p l a n t . Many p l a n t c h a r a c t e r i s t i c s ( e . g . , s i z e ) a r e i n t e n s i f i e d by an i n c r e a s e i n p l o i d y l e v e l . However, G u s t a f s s o n a l s o p o i n t s o u t (and d i s c u s s e s a t l e n g t h ) the a s s o c i a t i o n between p o l y p l o i d y and s e l f - s t e r i l i t y . C l e a r l y , the a b i l i t y t o r e p r o d u c e a p o m i c t i c a l l y would be o f g r e a t v a l u e t o a p o l y p l o i d t h a t i s s t e r i l e because i t i s a u t o p l o i d , o r because i t has an odd number o f chromosome s e t s . I f i t c a nnot r e p r o d u c e by t h i s means, i t w i l l be u nable t o p r o p a g a t e a t a l l and w i l l not s u r v i v e . S i n c e s e x u a l r e p r o d u c t i o n , w i t h i t s p o t e n t i a l f o r i n t r o d u c i n g v a r i a b i l i t y , has under most c o n d i t i o n s an advantage o v e r a s e x u a l r e p r o d u c t i o n , the c o r r e s p o n d -- 125 -i n g d i p l o i d p l a n t s c o n t i n u e t o r e p r o d u c e s e x u a l l y . R e l a t i v e l y few d i p l o i d , a p o m i c t i c p l a n t s p e c i e s a r e known ( S t e b b i n s 1950). A d i p l o i d a p o m i c t i c form o f H_. umbellatum has been r e p o r t e d by G e n t c h e f f (1941) but a p p e a r s t o be r a r e . S t e b b i n s (1950) and Mosquin (1966a) have o b s e r v e d t h a t a p o m i c t s u s u a l l y o r i g i n a t e from o u t c r o s s i n g s p e c i e s . The r e p r o d u c t i v e r e s o u r c e s o f an -o p t i m a l l y a d a p t e d p l a n t s p e c i e s would be e x p e c t e d t o be d i v i d e d between the promotion o f v a r i a b i l i t y (which e n a b l e s t h e s p e c i e s t o a d a p t t o a range o f d i f f e r e n t e n v i r o n m e n t a l s i t u a t i o n s ) and the p r o p a g a t i o n o f genomes which have s u r v i v e d the p r o c e s s o f n a t u r a l s e l e c t i o n , and have t h e r e b y proved t h e m s e l v e s s u c c e s s f u l . G e n e t i c r e c o m b i n a t i o n i s promoted by o u t c r o s s i n g , but o u t c r o s s e d p l a n t s a r e dependent f o r p o l l e n t r a n s f e r on f a c t o r s n o t under t h e i r c o n t r o l ( e . g . , a v a i l a b i l i t y o f p o l l i n a t o r s ) . A s exual r e p r o d u c t i o n and i n b r e e d i n g both promote g e n e t i c 1 u n i f o r m i t y , but a r e o f t e n a more c e r t a i n way o f e n s u r i n g t h a t the n e x t g e n e r a t i o n w i l l be produced. The common o c c u r r e n c e o f p a r t i c u l a r r e p r o d u c t i v e p a t t e r n s i n c e r t a i n k i n d s o f h a b i t a t has been n o t e d by a number o f a u t h o r s ( S t e b b i n s 1950, Baker 1959, Davis & Heywood 1963, A l l a r d 1965, Mosquin1966a, M u l l i g a n & F i n d l a y . 1970, S t e b b i n s 1970). Asexual r e p r o d u c t i o n o r s e l f - f e r t i l i z a t i o n a r e commonly e n c o u n t e r e d i n s u c c e s s i o n a l h a b i t a t s , where the s u c c e s s o f a p l a n t s p e c i e s may depend on i t s a b i l i t y t o c o l o n i z e r a p i d l y ahead o f o t h e r i n v a d i n g s p e c i e s . In the N o r t h American H_. umbel l a t u m , a p o m i x i s n o t o n l y s e r v e s as a means o f o v e r c o m i n g t h e s t e r i l i t y r e s u l t i n g from t r i p l o i d y , but p e r m i t s abundant seed s e t under a l m o s t any c o n d i t i o n s . C o n s e q u e n t l y , t h i s s p e c i e s - 126 -i s w e l l s u i t e d t o s u c c e s s i o n a l h a b i t a t s . The m o r p h o l o g i c a l v a r i a t i o n f o u n d w i t h i n the H_. umbel!atum complex i n p l a n t s from d i f f e r e n t l o c a l i t i e s s u g g e s t s t h a t p l a n t s o f t h i s group a r e n o t o b l i g a t e a p o m i c t s , but a r e o c c a s i o n a l l y o u t c r o s s i n g . T h i s has l e d t o the e x i s t e n c e o f many a p o m i c t i c l i n e s , each d i f f e r i n g from the n e x t i n morphology and, p r o b a b l y , e c o l o g i c a l t o l e r a n c e s . Such a p a t t e r n g r e a t l y i n c r e a s e s the v a r i e t y o f a v a i l a b l e h a b i t a t s t h a t can be c o l o n i z e d . A c c o r d i n g t o A l l a r d ( 1 9 6 5 ) , a p a t t e r n c o m bining predominant i n b r e e d i n g ( o r o t h e r means o f p r o p a g a t i n g s i m i l a r g e n o t y p e s ) w i t h a s m a l l amount o f o u t c r o s s i n g i s c h a r a c t e r i s t i c o f a number o f the w o r l d ' s s u c c e s s f u l weeds. P l a n t s o f the H_. umbel l a t u m complex have l a r g e showy f l o w e r heads t h a t might be e x p e c t e d t o a t t r a c t p o l l i n a t o r s ; t h e y may s t i l l s e r v e t h i s f u n c t i o n a l t h o u g h v e r y l i t t l e f e r t i l e p o l l e n i s produlced. The d i s t u r b a n c e s seen i n p o l l e n d e v e l o p -ment may be e n t i r e l y the r e s u l t o f t r i p l o i d y , e x c e p t f o r t h i s , p o l l e n v i a b i l i t y might be much h i g h e r . On the o t h e r hand, i t i s p o s s i b l e t h a t s i z e o f f l o w e r head i s a n o n f u n c t i o n a l c a r r y o v e r from s e x u a l l y r e p r o d u c i n g a n c e s t o r s , o r s i m p l y the d i r e c t r e s u l t o f i n c r e a s e i n chromosome number. The p o p u l a t i o n s o f t h i s complex i n North America p r o b a b l y o r i g i n a t e d i n Europe, and r e a c h e d t h i s c o n t i n e n t v i a the B e r i n g Land B r i d g e i n t h e l a t e C e n o z o i c E r a ( Y u r t s e v 1972). The S i b e r i a n m a t e r i a l o f H_. umbellatum t h a t has so f a r been examined i s a l l t r i p l o i d , as i s o u r m a t e r i a l . There may a l s o have been su b s e q u e n t i n t r o d u c t i o n s o f m a t e r i a l f r o m Europe. The c e n t r e o f d i v e r s i t y f o r the subgenus E u h i e r a c i u m i s Europe, but o n l y a s m a l l p o r t i o n o f the v a r i a t i o n f o u n d i n t h e Old World i s r e p r e s e n t e d on t h i s c o n t i n e n t . - 127 -The N orth American m a t e r i a l has shown a t e n d e n c y t o become g e o g r a p h i c a l l y h e t e r o g e n e o u s ; H_. canadense has n o t been found i n B r i t i s h Columbia (s e e d i s c u s s i o n on n e x t p a g e ) , and i s a p p a r e n t l y r e s t r i c t e d t o e a s t e r n N orth A m e r i c a . T h i s may be the r e s u l t o f d i v e r g e n c e w i t h i n t h e group a f t e r i t s a r r i v a l , o r s o r t i n g o f a l r e a d y p r e s e n t genotypes i n i m m i g r a t i n g p o p u l a t i o n s due t o d i f f e r e n c e s i n h a b i t a t p r e f e r e n c e . W i t h i n t h i s group o f p l a n t s , not o n l y i s v a r i a t i o n i n morphology u n r e l a t e d t o t h a t i n the e n v i r o n m e n t , but d i f f e r e n t m o r p h o l o g i c a l c h a r a c t e r s show l i t t l e o r no c o r r e l a t i o n w i t h one a n o t h e r . A l t h o u g h i t might be e x p e c t e d t h a t d i a g n o s t i c c h a r a c t e r s would be more h i g h l y c o r r e l a t e d , t h i s l a c k o f c o r r e l a t i o n extends even t o t h o s e c h a r a c t e r s t h a t have been used t o d i s t i n g u i s h H_. umbellatum and H_. canadense (as d e f i n e d by G l e a s o n , 1963). These two extremes have m o r p h o l o g i c a l l y i n d i s t i n g u i s h a b l e s o m a t i c chromosomes, and s i m i l a r k i n d s o f a b n o r m a l i t i e s i n the p o l l e n m i c r o s p o r o c y t e s . V a r i a b i l i t y o f f l a v o n o i d c h e m i s t r y w i t h i n t h i s group was not a s s e s s e d . However, e x a m i n a t i o n o f two s i n g l e - p l a n t e x t r a c t s i n a d d i t i o n t o t h e main e x t r a c t showed t h a t c h e m i c a l v a r i a t i o n does e x i s t , and i t i s p r o b a b l y c l i n a l a l s o . I t i s e v i d e n t t h a t the s e p a r a t i o n o f the N o r t h American H_. umbel!atum complex i n t o s p e c i e s i n v o l v e s l a r g e l y a r b i t r a r y d e c i s i o n s . T h e r e a r e no m o r p h o l o g i c a l d i s c o n t i n u i t i e s , and a d i s c u s s i o n o f " r e p r o d u c t i v e i s o l a t i o n " i n t h i s p r e d o m i n a n t l y a s e x u a l group would have l i t t l e meaning. I t i s p r o b a b l y j u s t i f i a b l e , on the b a s i s o f custom and c o n v e n i e n c e , t o r e t a i n the names H_. umbellatum L. and canadense Michx. f o r t h o s e specimens t h a t p o s s e s s s u b c o n i c h a i r s and t h o s e t h a t l a c k them, r e s p e c t i v e l y . T h e r e i s a t e n d e n c y - 128 -(though i t i s not v e r y pronounced) f o r the l a t t e r p l a n t s t o have w i d e r l e a v e s , on t h e a v e r a g e , t h a n t h e f o r m e r . S i n c e I have examined o n l y a few specimens o f t y p i c a l H_. canadense, t h e o p i n i o n o f f e r e d here i s t e n t a t i v e o n l y . With r e s p e c t t o m a t e r i a l from B r i t i s h C o lumbia, however, I can f i n d no d i f f e r e n c e s o f s u f f i c i e n t magnitude t o w a r r a n t s e p a r a t i o n o f o u r m a t e r i a l i n t o more than one s p e c i e s . The m o r p h o l o g i c a l extreme r e f e r r e d t o as H_. canadense Michx. o c c u r s v e r y r a r e l y , i f a t a l l , i n w e s t e r n Canada (an o b s e r v a t i o n t h a t was f i r s t made by..Lepage, 1960). I s u g g e s t t h a t a l l B r i t i s h Columbia m a t e r i a l o f t h i s group s h o u l d be i n c l u d e d i n H_. umbel latum L. T h e r e seems t o be no r e a s o n t o r e t a i n the name HL s c a b r i u s c u l u m Schwein. f o r any o f t h e N o r t h American p l a n t s , o r t o r e c o g n i z e any i n f r a s p e c i f i c t a x a w i t h i n H_. umbel!atum i n B r i t i s h Columbia. (2) The H i e r a c i u m s c o u l e r i complex. The t h r e e s p e c i e s i n c l u d e d h e r e d i s p l a y c l i n a l v a r i a t i o n i n t h e d e n s i t y o f s e t o s e h a i r s on the l e a v e s , stem and i n v o l u c r e . T h i s v a r i a t i o n i n pubescence a p p e a r s t o be c o r r e l a t e d t o some e x t e n t w i t h d i f f e r e n c e s i n h a b i t a t p r e f e r e n c e . - A c c o r d i n g t o Daubenmire (1959) and S a v i l e ( 1 9 7 2 ) , h a i r d e n s i t y i n a g i v e n s p e c i e s i s c o r r e l a t e d i n v e r s e l y w i t h abundance o f m o i s t u r e and d i r e c t l y w i t h a v a i l a b i l i t y o f l i g h t . T r ichomes may a s s i s t i n r e d u c i n g water l o s s by i n t e r f e r i n g w i t h c o n v e c t i o n c u r r e n t s t h a t c a r r y m o i s t u r e from the stomata (Daubenmire 1959). They reduc e the e f f e c t i v e i n t e n s i t y o f sun-l i g h t by s h a d i n g t h e l i v i n g c e l l s o f t h e l e a f , and t h e y a r e f r e q u e n t l y p a l e i n c o l o u r , which l i g h t e n s t h e c o l o u r o f t h e f o l i a g e and r e s u l t s i n g r e a t e r r e f l e c t i o n o f i n c i d e n t l i g h t ( S a v i l e 1972). P l a n t s exposed t o b r i g h t s u n l i g h t a r e f r e q u e n t l y more p u b e s c e n t than r e l a t e d s p e c i e s o f s h a d i e r h a b i t a t s . The - 129 -r e l a t i o n s h i p between t r i c h o m e d e n s i t y and i n t e n s i t y o f l i g h t may be i n d i r e c t , s i n c e l e s s l i g h t r e s u l t s i n lower t e m p e r a t u r e s and hence a s l o w e r t r a n s -p i r a t i o n r a t e . I t a l s o l e a d s t o l e s s r a p i d e v a p o r a t i o n and d i s a p p e a r a n c e o f a v a i l a b l e water i n the p l a n t ' s s u r r o u n d i n g s . On t h e o t h e r hand, t h e r e i s d e f i n i t e e v i d e n c e t h a t t h e i n t e n s i t y o f f u l l s u n l i g h t i s s u p r a o p t i m a l f o r p h o t o s y n t h e s i s i n many p l a n t s (Daubenmire 1959). R e c e n t l y , L e v i n (1973) has summarized t h e e v i d e n c e f o r a n o t h e r f u n c t i o n o f t r i c h o m e s : p r o t e c t i o n a g a i n s t p r e d a t o r s ( e s p e c i a l l y i n s e c t s ) . He g i v e s examples ( G l y c i n e max, Gossypium h i r s u t u m ) o f p l a n t s p e c i e s i n which d e n s i t y o f pubescence has been shown t o be i n v e r s e l y r e l a t e d t o i n t e n s i t y o f i n s e c t a t t a c k . L e v i n s u g g e s t s t h a t v a r i a t i o n s i n h a i r i n e s s among d i f f e r e n t h a b i t a t s o r d i f f e r e n t p a r t s o f the g e o g r a p h i c range may r e f l e c t the r e l a t i v e abundance o f p r e d a t o r s . In t h i s group, d i f f e r e n c e s i n pubescence are p r o b a b l y r e l a t e d t o d i f f e r e n c e s i n a v a i l a b i l i t y o f water. H i e r a c i u m s c o u l e r i ( a t l e a s t i n i t s most g l a b r o u s phase) i s u s u a l l y found i n damper o r s h a d i e r h a b i t a t s . The d i f f e r e n c e i n h a b i t a t p r e f e r e n c e - i s l e s s a p p a r e n t between H_. a l b e r t i n u m and H. c y n o g l o s s o i d e s t h a n between HL c y n o g l o s s o i d e s and H^ . s c o u l e r i . However, r e l a t i v e l y l i t t l e i n f o r m a t i o n i s a v a i l a b l e on t h i s p o i n t , s i n c e t h e f i r s t two t a x a mentioned were found growing t o g e t h e r a t o n l y two s i t e s . At one o f t h e s e t h e y were growing i n t e r m i n g l e d ; a t the o t h e r , H_. a l b e r t i n u m was growing i n a d r i e r , h i g h e r - e l e v a t i o n s i t e than H_. c y n o g l o s s o i d e s . F u r t h e r d o c u m e n t a t i o n i s r e q u i r e d b e f o r e d e f i n i t e c o n c l u s i o n s can be drawn r e g a r d i n g e c o l o g i c a l d i f f e r e n c e s w i t h i n t h i s group. - 130 -The p l a n t s a r e f o u n d a t m i d d l e t o m o d e r a t e l y h i g h e l e v a t i o n s , i n s t a b l e o r a t l e a s t s l o w l y c h a n g i n g communities. A l l t h r e e t a x a a r e d i p l o i d and exogamous. I t i s p r o b a b l e t h a t t h e y p o s s e s s a g e n e t i c a l l y c o n t r o l l e d s e l f -i n c o m p a t i b i l i t y mechanism o f some s o r t , s i n c e a c c o r d i n g t o my o b s e r v a t i o n s t h e r e was ample t r a n s f e r o f p o l l e n t o the s t i g m a , e s p e c i a l l y i n f l o w e r heads s u b j e c t e d t o m e c h a n i c a l d i s t u r b a n c e . The p l a n t s o f t h i s group produce abundant and h i g h l y f e r t i l e p o l l e n , and t h e f l o w e r heads a r e r e l a t i v e l y l a r g e and showy. C l e a r l y t h e y a r e adapted f o r o u t c r o s s i n g . V a r i o u s a u t h o r s ( S t e b b i n s 1950, Davis & Heywood 1963, Mosquin 1966a) have remarked t h a t f l o w e r i n g p l a n t s o c c u r r i n g i n p i o n e e r h a b i t a t s a r e o f t e n i n b r e e d e r s , and t h o s e o f mature h a b i t a t s more commonly o u t c r o s s i n g ( s e e a l s o d i s c u s s i o n on page 125). T h i s i s t r u e o f f e r n s as w e l l ( L l o y d 1974). T h i s t r e n d i s o f e v o l u t i o n a r y s i g n i f i c a n c e . In c l i m a x c o mmunities, the v a r i a b i l i t y r e s u l t i n g from o u t c r o s s i n g c o n f e r s an advantage i n i n t e r s p e c i f i c c o m p e t i t i o n ( D a v i s & Heywood 1963). Such communities have a s t a b l e s p e c i e s c o m p o s i t i o n and appear on the s u r f a c e t o be dhanging v e r y l i t t l e . A c c o r d i n g t o Van V a l e n (1973), however, each s p e c i e s i s c o n t i n u a l l y p r o d u c i n g new g e n e t i c com-b i n a t i o n s t h a t c h a l l e n g e the a d a p t a b i l i t y o f o t h e r s p e c i e s competing f o r the same r e s o u r c e s ; thus each o f t h e s p e c i e s must be c o n t i n u a l l y a d a p t i n g and c h a n g i n g i n o r d e r t o r e t a i n i t s p o s i t i o n i n t h e community. T h i s i s b e s t a c h i e v e d by a l a r g e degree o f o u t c r o s s i n g . I n t e r e s t i n g l y , seed g e r m i n a t i o n a p p e a r s t o be low and s p o r a d i c i n t h i s group o f hawkweeds. A l l seed f o r b r e e d i n g e x p e r i m e n t s was c o l l e c t e d d u r i n g J u l y and August, w e l l b e f o r e f a l l f r o s t s , and t h e r e may be a s t r a t i f i c a t i o n - 131 -r e q u i r e m e n t t h a t was not met. The seeds o f H i e r a c i u m umbellatum appear t o have such a r e q u i r e m e n t ; a s i n g l e c o l l e c t i o n o f seed made on November 4, 1972 g e r m i n a t e d much more r e a d i l y than o t h e r c o l l e c t i o n s o f seed made i n t h e p r e v i o u s summer. H i e r a c i u m umbellatum and the t h r e e s p e c i e s d i s c u s s e d here a r e exposed to. s i m i l a r c l i m a t i c c o n d i t i o n s ( a l t h o u g h t h e y a r e n o t v e r y c l o s e l y r e l a t e d ) and t h e i r seeds may have t h e same g e r m i n a t i o n r e q u i r e m e n t s . On the o t h e r hand, i t may be t h a t g e r m i n a t i o n r e q u i r e m e n t s f o r the l a t t e r group a r e more e x a c t . Of t h e s p e c i e s grown, t h e members o f the H_. s c o u l e r i complex were t h e most d i f f i c u l t o f a l l t o r a i s e under c u l t i v a t i o n . There a r e no e s s e n t i a l d i f f e r e n c e s among the t h r e e s p e c i e s o f the H i e r a c i u m s c o u l e r i complex, o t h e r than t h o s e a l r e a d y d i s c u s s e d . E x c e p t f o r d i f f e r e n c e s i n t h e d e n s i t y o f s e t o s e h a i r s , t h e y a r e i n d i s t i n g u i s h a b l e . T h e i r chromosome s t r u c t u r e and r e p r o d u c t i v e b e h a v i o u r a r e the same, t h e i r f l a v o n o i d c h e m i s t r y i s v e r y s i m i l a r , and t h e y a r e c o m p l e t e l y i n t e r f e r t i l e . I t seems c l e a r t h a t t h e s e t h r e e t a x a have a r e c e n t common a n c e s t r y . The i n t e r g r a d a t i o n between them might be due t o h y b r i d i z a t i o n between p r e v i o u s l y d i s t i n c t t a x a , but t h i s seems u n l i k e l y , s i n c e t h e i r r a n g e s a r e e s s e n t i a l l y s y m p a t r i c and t h e i r h a b i t a t p r e f e r e n c e s a r e n o t s u f f i c i e n t l y d i f f e r e n t t o i s o l a t e them r e p r o d u c t i v e l y . T h e i r d i v e r g e n c e f r o m a s i n g l e m o r p h o l o g i c a l type may be t h e r e s u l t o f g e n e t i c d r i f t , s i n c e I have q u i t e o f t e n found s m a l l p o p u l a t i o n s o f a few p l a n t s a p p a r e n t l y i s o l a t e d by some d i s t a n c e from a d j a c e n t p o p u l a t i o n s by r e g i o n s o f u n s u i t a b l e h a b i t a t . T h i s i s s p e c u l a t i v e , however, as d i s t a n c e s between p o p u l a t i o n s i n a g i v e n a r e a c a n n o t be d e t e r m i n e d a c c u r a t e l y w i t h o u t a d e t a i l e d i n v e s t i g a t i o n o f the a r e a . Other f a c t o r s a r e o f t e n i n v o l v e d , f o r example the range and c o n s t a n c y o f a v a i l a b l e p o l l i n a t o r s . - 132 -D i v e r g e n c e may a l s o have been a r e s p o n s e t o h a b i t a t h e t e r o g e n e i t y . I t i s now w e l l e s t a b l i s h e d e x p e r i m e n t a l l y ( G i b s o n & Thoday 1973, Soans e t a l 1974) t h a t d i v e r g e n c e can o c c u r i n s y m p a t r i c p o p u l a t i o n s even though t h e r e i s gene f l o w between them, p r o v i d e d t h a t the s e l e c t i v e p r e s s u r e i s s u f f i c i e n t . Most o f t h e s e e x p e r i m e n t s have been done on a n i m a l s , but models f o r , and a p p a r e n t examples o f , s p e c i a t i o n o f t h i s t y p e have a l s o been d e s c r i b e d f o r p l a n t s (Straw 1955). S i n c e both m o r p h o l o g i c a l d i s c o n t i n u i t y and r e p r o d u c t i v e i s o l a t i o n a r e l a c k i n g i n t h i s group, t h e p r e s e n t d i s p o s i t i o n o f the t h r e e t a x a i s c l e a r l y i n a d e q u a t e . They a r e p r o b a b l y b e s t r e g a r d e d as v a r i e t i e s o f a s i n g l e s p e c i e s . [ P i p e r (1906) and P i p e r & B e a t t i e ( 1 9 1 5 ) , a l t h o u g h t h e y proposed no f o r m a l taxonomic changes, were among the e a r l i e s t a u t h o r s t o s u g g e s t t h i s . These a u t h o r s d e s c r i b e d , under d i f f e r e n t names, a p p r o x i m a t e l y the same s p e c i e s as has C r o n q u i s t (1955a).] V a r i e t a l s t a t u s would seem most a p p r o p r i a t e , s i n c e t h e r e i s an i n c r e a s i n g t e n d e n c y f o r many t a x o n o m i s t s t o r e s e r v e the rank o f s u b s p e c i e s f o r g e o g r a p h i c a l l y s e p a r a t e d v a r i a n t s ( D a v i s & Heywood 1963). The t h r e e s p e c i e s would t h e r e f o r e become s e g r e g a t e s o f H i e r a c i u m s c o u l e r i : v a r . a l b e r t i n u m , v a r . c y n o g l o s s o i d e s , and v a r . s c o u l e r i . The c i r c u m s c r i p t i o n o f the names has a l s o been somewhat vague. T h i s due p a r t l y t o the f a c t t h a t as each new s p e c i e s was d e s c r i b e d , t h e range o f v a r i a t i o n encompassed by a l r e a d y e x i s t i n g s p e c i e s names became more r e s t r i c t e d , and the a u t h o r s o f t h e s e l a t e r names d i d n o t h i n g t o r e l i e v e t he c o n f u s i o n . The t y p e d e s c r i p t i o n o f H- s c o u l e r i s u g g e s t s t h a t t h e t y p e specimen p r o b a b l y i s c l o s e r t o H_. cyno- g l o s s o i d e s than t o p r e s e n t - d a y H_. s c o u l e r i . T y p i c a l H_. s c o u l e r i i s g l a b r o u s ( e x c e p t f o r minute s t e l l a t e h a i r s ) , o r v e r y s p a r s e l y c o v e r e d on the lower - 133 -l e a v e s w i t h s e t o s e h a i r s . A c a s e c o u l d perhaps be made f o r s e p a r a t i n g H_. s c o u l e r i from t h e o t h e r two t a x a a t t h e l e v e l o f s u b s p e c i e s on t h e b a s i s o f i t s a p p a r e n t l y more pronounced d i f f e r e n c e i n h a b i t a t p r e f e r e n c e , a l t h o u g h the t h r e e t a x a a r e n o t g e o g r a p h i c a l l y s e p a r a t e d . A f o r m a l change o f names i s not p r e s e n t e d h e r e , f o r a number o f r e a s o n s . In t h i s s t u d y I have examined l a r g e numbers o f Canadian specimens o f t h i s group, but o n l y a few American s p e c i m e n s , and a l l t h r e e o f t h e s e t a x a e x t e n d southward as f a r as n o r t h e r n C a l i f o r n i a . T h e i r p a t t e r n s o f v a r i a b i l i t y i n the s o u t h e r n p a r t o f t h e i r range may o r may n o t remain t h e same. In a d d i t i o n , t h e r e a r e a number o f o t h e r s p e c i e s which resemble t h e s e t h r e e i n many ways and whose r e l a t i o n s h i p t o the B r i t i s h Columbia s p e c i e s i s n o t c l e a r . In p a r t i c u l a r , H_. a l b e r t i n u m and an endemic s p e c i e s o f the Columbia Gorge, H_. l o n g i b e r b e H o w e l l , a r e v e r y s i m i l a r . A l t h o u g h o u r t h r e e t a x a , j u d g i n g from p u b l i s h e d d e s c r i p t i o n s (Abrams & F e r r i s 1960), appear more s i m i l a r t o one a n o t h e r than t o t h e s e s o u t h e r n s p e c i e s , t h i s needs t o be v e r i f i e d by e x p e r i m e n t a l e v i d e n c e . (3) H i e r a c i u m a l b i f l o r u m . H i e r a c i u m a l b i f l o r u m r e s e m b l e s t he s p e c i e s o f the H_. s c o u l e r i complex i n morphology and i n g e n e r a l h a b i t . I t o c c u r s a t somewhat lower e l e v a t i o n s than the l a t t e r group ( a l t h o u g h t h e r e i s c o n s i d e r a b l e o v e r l a p ) , and i t i s commonly e n c o u n t e r e d i n d i s t u r b e d s i t e s . I t i s m o r p h o l o g i c a l l y somewhat v a r i a b l e , but t h e r e i s no a p p a r e n t c o r r e l a t i o n w i t h g e o g r a p h i c a l o r v e c o l o g i c a l d i f f e r e n c e s . The v a r i a b i l i t y o f the number o f f l o w e r heads (and p r o b a b l y o f p l a n t h e i g h t , though t h i s was not measured) s u g g e s t s a - 134 -c o n s i d e r a b l e degree o f p h e n o t y p i c p l a s t i c i t y . A comparison o f the a d a p t a t i o n s o f H_. a l b i f l o r u m and o f the H_. s c o u l e r i group to t h e i r r e s p e c t i v e h a b i t a t s i s o f c o n s i d e r a b l e i n t e r e s t . H i e r a c i u m  a l b i f l o r u m i s d i p l o i d and p r e d o m i n a n t l y i n b r e e d i n g . I t s p o l l e n i s h i g h l y f e r t i l e , but much l e s s abundant t h a n i n t h e s p e c i e s o f t h e H_. s c o u l e r i complex (though more abundant t h a n i n H_. umbellatum). A l s o the f l o w e r heads a r e s m a l l e r and t h e c o r o l l a s l e s s b r i g h t l y c o l o u r e d . T h i s s p e c i e s i s p r o b a b l y o u t c r o s s e d some o f t h e t i m e , as i t i s s l i g h t l y p r o t a n d r o u s ( p o l l e n g r a i n s a r e v i s i b l e on the a n t h e r s and s t y l e b e f o r e the s t i g m a t i c s u r f a c e s have u n f o l d e d ) . However, the l a c k o f c o n s p i c u o u s a d a p t a t i o n s d e s i g n e d t o a t t r a c t p o l l i n a t o r s i n d i c a t e s t h a t autogamy i s u s u a l . H i e r a c i u m a l b i f l o r u m i s an i l l u s t r a t i o n o f t h e f a c t t h a t weedy p l a n t s p e c i e s a r e f r e q u e n t l y autogamous ( M u l l i g a n & F i n d l a y 1970, M u l l i g a n 1972). S t e b b i n s (1970) s u g g e s t s t h a t the advantage o f autogamy i n t h e c o l o n i z i n g o f new h a b i t a t s i s e s p e c i a l l y g r e a t a t the edge o f a s p e c i e s ' s r a n g e , where n o r m a l l y a v a i l a b l e p o l l i n a t o r s may be a b s e n t . As A l l a r d (1965) has p o i n t e d o u t , the c o m b i n a t i o n o f s e l f i n g and o c c a s i o n a l o u t c r o s s i n g i s w e l l s u i t e d t o weedy s p e c i e s , s i n c e i t p e r m i t s t h e p r o d u c t i o n o f d i f f e r e n t g e n e t i c c o m b i n a t i o n s and a t the same time a l l o w s t h o s e t h a t a r e most s u c c e s s f u l t o be p r o p a g a t e d . E x p e r i m e n t s done by A l l a r d show t h a t t h e h e t e r o z y g o s i t y r e s u l t i n g from a s i n g l e o u t c r o s s may c o n t i n u e t o be e v i d e n t t h r o u g h many g e n e r a t i o n s o f i n b r e e d i n g . P l a s t i c i t y o f t h e phenotype s e r v e s t o g i v e a d d i t i o n a l f l e x i b i l i t y t o the g e n e t i c a l l y u n i f o r m p o p u l a t i o n s r e s u l t i n g from s e l f i n g , and i s o f p a r t i c u l a r a d a p t i v e v a l u e t o a c o l o n i z i n g s p e c i e s i n a h e t e r o g e n e o u s o r r a p i d l y c h a n g i n g h a b i t a t . NOTE: Page 135 does not exist. - 136 -Seed g e r m i n a t i o n i n H_. a l b i f l o r u m i s v e r y g r a d u a l , o c c u r r i n g from two t o e i g h t weeks a f t e r p l a n t i n g . In t h i s i t r e sembles t h e H_. s c o u l e r i complex, though a s u c c e s s i o n a l s p e c i e s m i ght be e x p e c t e d t o have more r a p i d l y g e r m i n a t i n g s e e d s . A s t u d y by H o l t (1972) on Daucus c a r o t a ( w i l d c a r r o t ) i n s u c c e s s i o n a l h a b i t a t s showed t h a t when a new a r e a became a v a i l a b l e f o r c o l o n i z a t i o n , e a r l y - a r r i v i n g p l a n t s had a h i g h e r seed g e r m i n a t i o n r a t e and more r a p i d and abundant seed s e t than l a t e a r r i v a l s . However, i t seems l i k e l y t h a t i n H. a l b i f l o r u m t h i s g e r m i n a t i o n p a t t e r n i s an a d a p t a t i o n t o e n v i r o n m e n t a l c o n d i t i o n s . I f t h e seeds g e r m i n a t e o v e r a l o n g p e r i o d , l a t e f r o s t s and o t h e r v a g a r i e s o f the c l i m a t e w i l l k i l l a much s m a l l e r p r o p o r t i o n o f each y e a r ' s s e e d l i n g s . T h i s s p e c i e s i s m o r p h o l o g i c a l l y and r e p r o d u c t i v e l y d i s t i n c t , and t a x o n o m i c a l l y i t i s s a t i s f a c t o r i l y t r e a t e d as a s i n g l e s p e c i e s . T h e r e seems to be no r e a s o n a b l e b a s i s f o r the i n t r a s p e c i f i c t a x a d e s c r i b e d by Zahn (1921-1923). A l t h o u g h a l b i f l o r u m i s somewhat v a r i a b l e , f u r t h e r s t u d y would be n e c e s s a r y t o s e p a r a t e g e n e t i c d i f f e r e n c e s from t h o s e r e s u l t i n g from the i n f l u e n c e o f the e n v i r o n m e n t . (4) The H i e r a c i u m t r i s t e - H i e r a c i u m g r a c i l e complex. These two s p e c i e s t e n d t o be s m a l l i n s i z e , as a r e many a r c t i c and a l p i n e s p e c i e s . They a r e v e r y seldom found i n s u c c e s s i o n a l h a b i t a t s . They d i s p l a y v a r i a t i o n i n pubescence which app e a r s t o be more o r l e s s c o r r e l a t e d w i t h l a t i t u d e . Dense h a i r i n e s s i s q u i t e common i n h i g h - e l e v a t i o n p l a n t s (Hedberg 1964, S a v i l e 1972) and t h e s e a u t h o r s s u g g e s t t h a t i t s e r v e s as p r o t e c t i o n a g a i n s t t h e i n t e n s e l i g h t found i n a l p i n e h a b i t a t s ( e s p e c i a l l y a t low - 137 -l a t i t u d e s ) . T h i s does not e x p l a i n pubescence o f a r c t i c p l a n t s , which a r e s u b j e c t t o l o n g days but not v e r y i n t e n s e i l l u m i n a t i o n . S a v i l e (1972) \. s u g g e s t s , however, t h a t h a i r s t r a p i n f r a r e d l i g h t r a d i a t e d by the p l a n t , c o n s e r v i n g h e a t by a "greenhouse e f f e c t " . In any c a s e , i n H_. t r i s t e and •H_. g r a c i l e t h e p a r t i c u l a r f u n c t i o n o f t h e d i f f e r e n t t y p e s o f h a i r s on t h e i n v o l u c r e remains o b s c u r e . N e i t h e r s p e c i e s has c o r r e s p o n d i n g l y abundant h a i r s on t h e f o l i a g e , as might be e x p e c t e d i f t h e above h y p o t h e s e s were t r u e , a l t h o u g h p o s s i b l y warmth may be o f p a r t i c u l a r i m p o r t a n c e i n the development o f r e p r o d u c t i v e s t r u c t u r e s . Both s p e c i e s a r e d i p l o i d . H i e r a c i u m g r a c i l e i s autogamous, w i t h p o l l e n not v e r y abundant but h i g h l y f e r t i l e . L i v e m a t e r i a l o f H_. t r i s t e was n o t a v a i l a b l e f o r t e s t i n g , but i t i s h i g h l y p r o b a b l e t h a t i t i s autogamous a l s o . Both Mosquin (1966a) and S a v i l e (1972) o b s e r v e d t h a t r e p r o d u c t i v e mechanisms promoting u n i f o r m i t y ( s e l f i n g , a p o m i x i s ) a r e common i n the A r c t i c , and t h o s e p r o m o t i n g v a r i a b i l i t y a r e r e l a t i v e l y r a r e . I t may be t h a t the v a r i a b i l i t y r e s u l t i n g from o u t c r o s s i n g would r e s u l t i n a l a r g e p r o p o r t i o n o f genotypes l a c k i n g i n f i t n e s s , which would be a l i a b i l i t y i n such a s t r i n g e n t c l i m a t e . On t h e o t h e r hand, perhaps mechanisms p r o m o t i n g g e n e t i c u n i f o r m i t y a r e s i m p l y t o l e r a t e d because t h e y a r e a s s o c i a t e d w i t h more r a p i d , r e l i a b l e methods o f r e p r o d u c t i o n ( S a v i l e 1972). The r e l a t i v e l a c k o f i n t e r s p e c i f i c c o m p e t i t i o n i n a r c t i c e n v i r o n m e n t s may mean t h a t a g i v e n h a b i t a t i s more s t a b l e , and hence more f a v o u r a b l e t o g e n e t i c a l l y u n i f o r m p o p u l a t i o n s , s i n c e the f a c t o r s t h a t l i m i t s u r v i v a l a r e a b i o t i c and a r e t h e r e f o r e n o t i n f l u e n c e d by a d a p t i v e changes i n the o r g a n i s m . - 138 -Both t h e s e s p e c i e s have s m a l l , r e l a t i v e l y i n c o n s p i c u o u s f l o w e r heads, as would be e x p e c t e d o f s e l f - p o l l i n a t i n g p l a n t s . However, P o j a r (1974) has g a t h e r e d e v i d e n c e s u g g e s t i n g t h a t HI. g r a c i l e i s sometimes o u t c r o s s e d . He o b s e r v e d p o l l i n a t i o n o f t h i s s p e c i e s by s y r p h i d f l i e s and by s h o r t - t o n g u e d bees, and d e s c r i b e d i t as "markedly p r o t a n d r o u s " . P r o t a n d r y i s n o r m a l l y a way o f p r o m o t i n g o u t c r o s s i n g . In t h e s p e c i e s o f H i e r a c i u m i n c l u d e d i n t h i s s t u d y , however, and perhaps i n many o t h e r members o f t h e f a m i l y A s t e r a c e a e as w e l l , t h e s t r u c t u r e o f the f l o w e r s i s such t h a t p r o t a n d r y may encourage s e l f i n g ( s e e d i s c u s s i o n o f f l o w e r s t r u c t u r e i n C h a p t e r I I I ) . In many s p e c i e s , s e l f i n g i s e n s u r e d i n any case by t h e f a c t t h a t the o u t e r f l o w e r s open b e f o r e the i n n e r ones and a r e p o l l i n a t e d by them. I o b s e r v e d p r o t a n d r y i n H_. g r a c i l e to be n o t v e r y pronounced, the d e h i s c e n c e o f the a n t h e r s p r e c e d i n g t h e u n f o l d i n g o f the s t i g m a t i c s u r f a c e s by about s i x h o u r s . The s t y l e i n a l m o s t a l l f l o r e t s was c o v e r e d w i t h p o l l e n a f t e r i t s passage t h r o u g h t h e r i n g o f a n t h e r s . P o l l e n g r a i n s were n o t found on t h e s t i g m a t i c s u r f a c e a t f i r s t , but the s l i g h t e s t d i s t u r b a n c e o f the f l o w e r head (by wind, i n s e c t s , o r the passage o f an a n i m a l ) , r e s u l t e d i n the t r a n s f e r o f p o l l e n t o the s t i g m a . A number o f a u t h o r s ( e . g . Mosquin 1971, P o j a r 1974) have s u g g e s t e d t h a t i n some h a b i t a t s t h e r e i s c o m p e t i t i o n among f l o w e r i n g p l a n t s f o r p o l l i n a t o r s . When t h i s i s the c a s e , autogamy may d e v e l o p , as a form o f n i c h e d i s p l a c e m e n t t o a v o i d such c o m p e t i t i o n ( S t e b b i n s 1970, L e v i n 1972). T h i s may be the r e a s o n f o r s e l f - f e r t i l i t y i n H_. g r a c i l e . T h i s s p e c i e s has o t h e r c h a r a c t e r i s t i c s t y p i c a l o f a l p i n e s p e c i e s . I t s seed does n o t r e q u i r e a p e r i o d o f s t r a t i f i c a t i o n , but g e r m i n a t e s r a p i d l y and - 139 -s i m u l t a n e o u s l y , and a h i g h p e r c e n t a g e o f i t i s f e r t i l e . T h i s has o b v i o u s v a l u e i n h a b i t a t s where the growing s e a s o n i s s h o r t , and an e a r l y s t a r t may make the d i f f e r e n c e between r e p r o d u c t i v e f a i l u r e o r s u c c e s s . In c o n t r a s t , the o t h e r s p e c i e s s t u d i e d , growing a t l o w e r e l e v a t i o n s , g e r m i n a t e more g r a d u a l l y s i n c e r a p i d i t y o f development i s n o t so c r i t i c a l l y i m p o r t a n t . These o t h e r two s p e c i e s , H_. umbellatum and H_. a l b i f l o r u m , appear t o have a low t e m p e r a t u r e r e q u i r e m e n t f o r seed g e r m i n a t i o n as w e l l . At h i g h e l e v a t i o n s , where H_. g r a c i l e i s f o u n d , t h e snow c o v e r may n o t d i s a p p e a r u n t i l June, by which time the a i r i s warm and growth can p r o c e e d unchecked by u n f a v o u r a b l e t e m p e r a t u r e s . H i e r a c i u m g r a c i l e and \]_. t r i s t e , as might be e x p e c t e d , f l o w e r e a r l i e r than any o f the o t h e r s p e c i e s under garden c o n d i t i o n s . Two p l a n t s o f H_. t r i s t e , grown from seed c o l l e c t e d near M e z i a d i n Lake n o r t h o f T e r r a c e , f l o w e r e d s l i g h t l y e a r l i e r (by a few d a y s ) than H_. g r a c i l e f r o m seed c o l l e c t e d a t t he same s i t e . These two t a x a d i f f e r i n t h r e e c o r r e l a t e d but i n d e p e n d e n t m o r p h o l o g i c a l c h a r a c t e r s : pubescence o f l e a v e s , and d e n s i t y o f g l a n d u l a r and o f p i l o s e h a i r s on the i n v o l u c r e . T h i s v a r i a t i o n i s n o t d i s c o n t i n u o u s but i n t e r m e d i a t e m o r p h o l o g i c a l t y p e s a r e c o m p a r a t i v e l y r a r e . The chromosomes o f t h e s e two s p e c i e s a r e v e r y s i m i l a r , and t h e y a r e p r o b a b l y i n t e r f e r t i l e ; a l l p l a n t s t h a t were c y t o l o g i c a l l y examined were m e i o t i c a l l y r e g u l a r , i n c l u d i n g m o r p h o l o g i c a l l y i n t e r m e d i a t e specimens. I f we assume t h a t d r y i n g has l i t t l e e f f e c t on f l a v o n o i d s , the two s p e c i e s a r e c h e m i c a l l y d i f f e r e n t . F l a v o n o i d s a r e r e l a t i v e l y s t a b l e , and McClure & A l s t o n (1964, 1966) found t h a t i n t h e i r - 140 -s t u d i e s on t h e Lemnaceae, v a r y i n g t h e e n v i r o n m e n t o f the p l a n t b e f o r e c o l l e c t i n g had l i t t l e e f f e c t on t h e c h e m i s t r y . However, o t h e r a u t h o r s have found v a r i a t i o n w i t h p l a n t age ( A s k e r & F r o s t 1972) and season o f the y e a r T a y l o r 1971), so c h e m i c a l v a r i a t i o n i s n o t always a r e f l e c t i o n o f s p e c i e s d i f f e r e n c e s . H i e r a c i u m t r i s t e i s most commonly f o u n d i n A l a s k a , e s p e c i a l l y on the A l e u t i a n I s l a n d s ; H i e r a c i u m g r a c i l e has a more s o u t h e r l y range. T h e i r d i s t r i b u t i o n p a t t e r n (see page 40) s u g g e s t s t h a t t h e i r d i v e r g e n c e i n t o s e p a r a t e t a x a i s t h e r e s u l t o f g l a c i a t i o n . As i c e advanced o v e r the c o n t i n e n t , the p l a n t s r e t r e a t e d b e f o r e i t , some p o p u l a t i o n s m i g r a t i n g southward i n t o the c o n t i n e n t a l U n i t e d S t a t e s and o t h e r s westward i n t o t h e A l a s k a n r e f u g i u m . We have no d i r e c t knowledge o f how f a r s o u t h H. g r a c i l e may have extended d u r i n g the i c e age; however, p l a n t s t h a t a r e r e c o g n i z a b l y H_. g r a c i l e o c c u r i n t h e C h i l e a n Andes. The range o f t h i s s p e c i e s must have extended t o the mountains on the e q u a t o r , and as the c l i m a t e became m i l d e r , moved o u t both northward and wouthward. The A l a s k a n p o p u l a t i o n s were p r o b a b l y exposed t o a h a r s h e r e n v i r o n m e n t , and hence were under s t r o n g e r s e l e c t i v e p r e s s u r e t o d e v e l o p a d a p t a t i o n s t o c o l d weather, t h a n were t h e more s o u t h e r l y p o p u l a t i o n s . The A l a s k a n p l a n t s t h e r e f o r e e v o l v e d the w o o l l y i n v o l u c r e and more,.pubescent l e a v e s we now a s s o c i a t e w i t h IH. t r i s t e . S i n c e the r e t r e a t o f t h e g l a c i e r s , both s p e c i e s have s p r e a d outward a g a i n — H i e r a c i u m g r a c i l e n o r t h w a r d , and H_. t r i s t e e a s t i n t o Canada and west i n t o t h e Kamchatka p e n i n s u l a . Upon i n i t i a l i n s p e c t i o n , H_. t r i s t e and H_. g r a c i l e appear t o form a n o r t h - s o u t h c l i n e . F u r t h e r i n v e s t i g a t i o n shows, however, t h a t t h e f r e q u e n c y - 141 -o f m o r p h o l o g i c a l l y i n t e r m e d i a t e specimens i s a c t u a l l y r a t h e r low, most p l a n t s b e i n g r e a d i l y a s s i g n a b l e t o one o f two groups ( s e e C h a p t e r I I ) . However, t h e r e l a t i v e p r o p o r t i o n o f t r i s t e - t y p e and g r a c i l e - t y p e specimens v a r i e s c l i n a l l y from n o r t h t o s o u t h . In view o f the bimodal p a t t e r n o f m o r p h o l o g i c a l v a r i a t i o n i n t h i s group, the d i f f e r e n c e s i n f l a v o n o i d c h e m i s t r y , and the p r o b a b l e d i f f e r e n c e s i n e c o l o g i c a l a d a p t a t i o n , i t seems b e s t t o r e t a i n t h e two t a x a as s p e c i e s . A l t h o u g h Gray (1876) and C a l d e r & T a y l o r (1968) grouped them t o g e t h e r under JH. t r i s t e , t he e v i d e n c e p r e s e n t e d here s u p p o r t s t h e i r s e p a r a t i o n . I t a l s o g i v e s a c l e a r e r p i c t u r e t h a n b e f o r e of. the n a t u r e o f t h e two predominant m o r p h o l o g i c a l t y p e s . T y p i c a l Ji. t r i s t e has abundant g r a y p i l o s e h a i r s on t h e i n v o l u c r e , and a complete absence o f g l a n d u l a r h a i r s ; t y p i c a l H^ . g r a c i l e has an a p p r o x i m a t e l y equal m i x t u r e o f f a i r l y s h o r t b l a c k g l a n d u l a r h a i r s and o f l o n g e r , n o n g l a n d u l a r p i l o s e h a i r s . The extreme form o f H. g r a c i l e , v a r . detonsum, i n which the n o n g l a n d u l a r h a i r s a r e few t o a b s e n t , i s r e l a t i v e l y r a r e . A s s o r t e d i n f r a s p e c i f i c t a x a have been proposed t o d e a l w i t h i n t e r m e d i a t e s between JH. g r a c i l e and H. t r i s t e (Zahn 1921-1923, P o r s i l d 1950). These i n c l u d e H_. g r a c i l e v a r . alaskanum Zahn, which d i f f e r s from t y p i c a l JH. g r a c i l e i n i t s s l i g h t l y more p i l o s e l e a v e s and more p i l o s e (though s t i l l g l a n d u l a r ) i n v o l u c r e and p e d u n c l e s ( H u l t e r i 1973), and t r i s t e v a r . t r i s t i f o r m e Zahn, which i s i n t e r m e d i a t e between H_. g r a c i l e v a r . alaskanum and t y p i c a l H. g r a c i l e . These i n t e r m e d i a t e c a t e g o r i e s a r e , i n my o p i n i o n , n o t n e c e s s a r y . In the f o r e g o i n g d i s c u s s i o n o f t h e v a r i o u s s p e c i e s g r o u p s , l i t t l e m ention has been made o f t h e a d a p t i v e s i g n i f i c a n c e o f c h e m i c a l p r o p e r t i e s . - 142 -Many c h a r a c t e r i s t i c s o f p l a n t s ( e . g . morphology, r e p r o d u c t i v e p a t t e r n s ) can be d i s c u s s e d i n terms o f t h e i r p r o b a b l e f u n c t i o n , and hence t h e i r s u r v i v a l v a l u e t o the s p e c i e s , but r e l a t i v e l y l i t t l e i s known about the f u n c t i o n o f s e c o n d a r y m e t a b o l i t e s . A commonly h e l d view i s t h a t f l a v o n o i d s , as w e l l as many o f the o t h e r " n o n - e s s e n t i a l " compounds produced by p l a n t s , s e r v e t o d i s c o u r a g e p r e d a t i o n by h e r b i v o r e s ( L e v i n 1971). Some f l a v o n o i d s a r e b i t t e r , a t l e a s t t o humans. In some f l o w e r i n g p l a n t s , f l a v o n o i d s a r e r e s p o n s i b l e f o r the a b s o r p t i o n o f u l t r a v i o l e t l i g h t i n n e c t a r g u i d e s (Thompson e t a l 1972), and hence s e r v e a f u n c t i o n i n a t t r a c t i n g p o l l i n a t o r s . Many s p e c i e s t h a t l a c k n e c t a r g u i d e s , however, c o n t a i n f l a v o n o i d s . In any c a s e , e x i s t i n g e x p l a n a t i o n s o f the f u n c t i o n o f f l a v o n o i d s t h u s f a r e x t e n d o n l y t o the c l a s s o f compounds as a whole. The f l a v o n o i d s f o u n d w i t h i n a group o f r e l a t e d s p e c i e s may d i f f e r i n v e r y minor ways, and we a r e s t i l l u n a b l e t o e x p l a i n how such c l o s e l y r e l a t e d compounds d i f f e r i n a d a p t i v e v a l u e . (5) R e l a t i o n s h i p s between s e c t i o n s . E x c e p t f o r H i e r a c i u m umbellatum, a l l t h e s p e c i e s i n c l u d e d i n t h i s s t u d y b e l o n g t o the subgenus S t e n o t h e c a . T h i s subgenus has been d i v i d e d i n t o t h i r t e e n s e c t i o n s by Zahn (1921-1923), and H i e r a c i u m a l b i f l o r u m , the H_. s c o u l e r i complex and the H_. t r i s t e - H_. g r a c i l e complex a r e each p l a c e d i n d i f f e r e n t s e c t i o n s . The subgenus c o n t a i n s a h e t e r o g e n e o u s a r r a y o f s p e c i e s and i s w i d e s p r e a d i n both North and South A m e r i c a , and the use o f s e c t i o n s t o i n d i c a t e group a f f i n i t i e s i s c l e a r l y o f v a l u e . However, t h e t h r e e groups o f s p e c i e s mentioned above a r e v e r y c l o s e l y r e l a t e d , as i s shown by t h e i r i n t e r f e r t i l i t y . I t i s e v i d e n t t h a t the b o u n d a r i e s between s e c t i o n s a r e i n need o f r e v i s i o n . - 143 -The H i e r a c i u m s c o u l e r i complex, t o g e t h e r w i t h the r e l a t e d s p e c i e s t o the s o u t h , forms a w i d e s p r e a d and d i v e r s i f i e d c l u s t e r o f s p e c i e s w i t h i n t h e subgenus, and may be the s t a r t i n g p o i n t from which t h e o t h e r two groups i n c l u d e d i n t h i s s t u d y e v o l v e d . Davis ( 1 9 7 4 ) , whose f a m i l i a r i t y w i t h the genus i s m a i n l y d e r i v e d from t h e subgenera E u h i e r a c i u m and P i l o s e l l a , s u g g e s t s t h a t t h e s e s p e c i e s o f the subgenus S t e n o t h e c a have an a f f i n i t y w i t h the genus C r e p i s . H i e r a c i u m a l b i f l o r u m i s more c l o s e l y r e l a t e d t o the H_. s c o u l e r i complex, both m o r p h o l o g i c a l l y and chromosomally, than a r e HL t r i s t e and g r a c i l e . I t p r o b a b l y d i v e r g e d from the a n c e s t r a l t y p e l a t e r than d i d the l a t t e r two s p e c i e s . T h e r e i s some e v i d e n c e i n the l i t e r a t u r e t o s u p p o r t t h i s h y p o t h e s i s . Mosquin ( 1 9 6 6 a ) c o n s i d e r s autogamy i n the Canadian f l o r a t o be a d e r i v e d c o n d i t i o n . C r o n q u i s t (1955b), i n h i s d i s c u s s i o n o f t h e A s t e r a c e a e , s t a t e s t h a t n o n - y e l l o w c o r o l l a s and numerous but f e w - f l o w e r e d heads a r e advanced f e a t u r e s w i t h i n t h e f a m i l y . The H i e r a c i u m t r i s t e - \\_. g r a c i l e group i s i n some ways ( f o r example, c h e m i c a l l y ) more complex t h a n t h e members o f t h e H_. s c o u l e r i complex, and might be even o l d e r . I f t h i s i s s o , and i f i t has e v o l v e d f r o m the a n c e s t o r s o f t h e " l a t t e r group, the r a t e o f e v o l u t i o n i n t h i s complex has been s l o w e r , but t h i s c o u l d be i n f l u e n c e d by the t y p e o f h a b i t a t i t o c c u p i e s . In t h e absence o f f o s s i l d a t a such c o n c l u s i o n s must remain s p e c u l a t i v e . P o s s i b l e p h y l o g e n e t i c r e l a t i o n s h i p s between t h e s p e c i e s a r e shown i n F i g u r e 22. (6) The p o s i t i o n o f t h e genus H i e r a c i u m w i t h i n t h e C i c h o r i e a e . I t i s a w o r t h w h i l e endeavor t o make use o f d a t a from f i e l d s o t h e r than - 144 -F i g u r e 22. H y p o t h e t i c a l r e l a t i o n s h i p s among the western North American s p e c i e s o f H i e r a c i u m subgenus S t e n o t h e c a . H_. c y n o g l o s s o i d e s Arv.-Touv. H. s c o u l e r i Hook. H. a l b e r t i n u m F a r r 1H. a l b i f l o r u m Hook. ? H. l o n g i b e r b e Howell C a - l i f o r n i a n s p e c i e s : H_. argutum N u t t . 7 H_. h o r r i d u m F r i e s b o l a n d e r i Gray H_. g r e e n e i Gray H_. g r a c i l e Hook. H. t r i s t e W i l l d . p o s t u l a t e d a n c e s t o r - 145 -morphology t o h e l p d e t e r m i n e g e n e r i c r e l a t i o n s h i p s w i t h i n the C i c h o r i e a e and i t s s u b t r i b e s . C y t o l o g i c a l and c h e m i c a l s t u d i e s , though t h e s e have so f a r v b e e n few, a r e b e g i n n i n g t o show promise as s o u r c e s o f new i n f o r m a t i o n . As mentioned i n C h a p t e r V, t h e c h e m i c a l r e s u l t s p r e s e n t e d here o f f e r s u p p o r t f o r t h e t r a d i t i o n a l c l a s s i f i c a t i o n o f t h i s group based on morphology. H i e r a c i u m s p e c i e s i n B r i t i s h Columbia ( a t l e a s t t h o s e I have examined) show c h e m i c a l a f f i n i t i e s w i t h o t h e r genera i n t h e s u b t r i b e C r e p i d i n a e and have the same o r s i m i l a r f l a v o n o i d s . S t e b b i n s e t al_ (1953) made e x t e n s i v e use o f c y t o l o g i c a l i n f o r m a t i o n t o h e l p d e t e r m i n e r e l a t i o n s h i p s o f the genera w i t h i n the C i c h o r i e a e . The c y t o l o g i c a l d a t a g a t h e r e d f o r B r i t i s h Columbia hawkweeds, s e v e r a l o f which were not c o u n t e d by t h e s e a u t h o r s , c o r r o b o r a t e s t h e i r c o n c l u s i o n s . However, t h e r e a r e many gaps s t i l l t o be f i l l e d b e f o r e a complete p i c t u r e can be o b t a i n e d o f t h e p h y l o g e n e t i c r e l a t i o n s h i p s w i t h i n the C i c h o r i e a e . - 146 -A S y n o p s i s o f H i e r a c i u m S p e c i e s i n B r i t i s h Columbia. In B r i t i s h Columbia t h e r e a r e seven s p e c i e s o f H i e r a c i u m , r e p r e s e n t i n g two o f the f o u r s u b g e n e r a . Subgenus E u h i e r a c i u m c o n t a i n s a s i n g l e , v a r i a b l e , a p o m i c t i c s p e c i e s . Subgenus S t e n o t h e c a i s r e p r e s e n t e d by s i x s p e c i e s , which s h o u l d be r e d u c e d t o f o u r i f f u r t h e r i n v e s t i g a t i o n s w i t h i n t h e group y i e l d s u p p o r t f o r the f i n d i n g s p r e s e n t e d h e r e . Subgenus E u h i e r a c i u m . H i e r a c i u m umbellatum L. Sp; PI. 804. 1753. .Synonyms: HL s c a b r i u s c u l u m Schwein. H_. macranthum N u t t . JH. s u k s d o r f i i Gandoger Subgenus S t e n o t h e c a . H i e r a c i u m a l b i f l o r u m Hook. F l . Bor. Amer. 1: 298. 1833. Synonyms: H_. h e l l e r i Gandoger JH_. leptopondanthum Gandoger JH_. candelabrum Gandoger JH. a l b i f l o r u m s u b v a r . r o s e n d a h l i i Zahn JH. a l b i f l o r u m f . l y a l l i i Zahn JH. p a c i f i c u m Zahn H i e r a c i u m a l b e r t i n u m F a r r . Ottawa Nat. 20: 109. 1906. Synonym: H_. absonum Ma c b r i d e & Payson H i e r a c i u m c y n o g l o s s o i d e s Arv.-Touv. S p i c i l . H i e r . 20. 1881. Synonyms: HL g r i s e u m Rydb. JH. c u s i c k i i Gandoger JH_. r y d b e r g i i Zahn H. f l e t t i i S t . John & Warren. - 147 -Subgenus S t e n o t h e c a ( c o n t ' d ) H i e r a c i u m s c o u l e r i Hook. F l . Bor. Amer. 1: 298. 1833. Synonyms: H_. amplum Greene H_. c i n e r e u m Howell H_. i d a h o e n s e Gandoger H_. paddoense Gandoger H_. w a s h i n g t o n e n s e Gandoger H_. c a s c a d o r u m Zahn H_. b a b c o c k i i Zahn H_. c u s i c k i a n u m Zahn H_. c h e l a n n e n s e Zahn H_. chapacanum Zahn H_. hemipol i o d e s Zahn H_. p a r r y i Zahn H i e r a c i u m t r i s t e W i l l d . ex S p r e n g e l , S y s t . Veg. 3: 640. 1826. Synonyms: _H. t r i s t e v a r . t r i s t i f o r m e Zahn H i e r a c i u m g r a c i l e Hook. F l . Bor. Amer. 1: 298. 1833. v a r . g r a c i l e Synonyms: H. h o o k e r i S t e u d . H_. t r i s t e v a r . g r a c i l e Gray H_. t r i s t e s s p . g r a c i l e (A. Gray) C a l d e r & T a y l o r H_. g r a c i l e v a r . y u k o n e n s e P o r s i l d H. g r a c i l e v a r . minimum A. N e l s . v a r . detonsum G r a y . P r o c . Amer. Acad. 19: 67. 1883. 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