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Davidsonia Mar 1, 1979

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Array DAVIDSONIA
VOLUME 10 NUMBER 1
Spring 1979 Cover:
Plectritis congesta growing on rocky outcrops
in Whytecliff Park in Horseshoe Bay near West
Vancouver.
Cladothamnus pyroliflorus, Copperbush, is a
shrub of cool shaded subalpine forests and
streambanks west of the Cascades. The flowers
are an unusual shade of pale coppery-orange.
DAVIDSONIA
VOLUME 10 NUMBER 1
Spring 1979
Davidsonia is published quarterly by The Botanical Garden of The University of British
Columbia, Vancouver, British Columbia V6T 1W5. Annual subscription, six dollars. Single
numbers, one dollar and fifty cents, except for special issues. All information concerning subscriptions should be addressed to the Director of The Botanical Garden. Potential contributors
are invited to submit articles and/or illustrative material for review by the Editorial Board.
Acknowledgements
The pen and ink illustrations are by Mrs. Lesley Bohm. The photographs on pages 2 through
6 were taken by Helen Kennedy. The photographic reproductions of the winning entries in
Graphica Botanica (pages 7-12) were prepared by Tod Greenaway's Photographic Place of
Vancouver. The article on Plectritis was researched by Mrs. Sylvia Taylor, and Dr. F. R.
Ganders of the Department of Botany at UBC reviewed the manuscript. Editorial and layout
assistance was provided by Mrs. Sylvia Taylor and Mrs. Lorna Anderson.
ISSN 0045-9739
Second Class Mail Registration Number 3313 The Invisible Patterns of Flowers
HELEN KENNEDY* and FRED R. GANDERS**
A bee landing on a flower wastes little time exploring, but moves straight toward the source of
nectar. The bee can do this because the location of the nectar is clearly marked on many flowers, and
the bee has learned the markings. The site of nectar is often marked by contrasting colors, such as the
yellow "eye" of a blue Forget-me-not, or the series of dots that lead up the throat of the pendulous
flower of a Foxglove. Contrasting centres, streaks, spots or dots are common patterns on flowers,
and are called nectar guides. These color patterns guide the insect to the nectar source, and in the
process may position the insect so that it pollinates the flower. Floral patterns have other functions as
well. They serve to attract the potential pollinator in the first place, and they allow the insect to discriminate between the different species that may be flowering at the same time.
Of course, not all flowers have contrasting color patterns or nectar guides. However, some which
appear to be uniform in color in fact have invisible patterns. The common Dandelion appears solid
yellow to us, but to a bee the outer rays are yellow plus ultraviolet (UV), called "bee violet", and the
centre is yellow. Bees and some other insects can see ultraviolet in addition to colors of the visible
spectrum, and many flowers pollinated by bees have ultraviolet patterns superimposed upon
whatever visible patterns the flower shows. Ultraviolet patterns are invisible to us because the lens of
the human eye filters out UV wavelengths before they reach the retina.
The range of colors which humans see is called the visible spectrum, and ranges from violet at a
wavelength of 400 nanometers (nm) at the lower end of the spectrum through red with a wavelength
of 800 nm at the upper end. Beyond the visible at the upper end of the spectrum is infrared and at the
lower end ultraviolet, both invisible to humans. A bee's vision differs in that the spectrum it detects is
shifted to shorter wavelengths, ranging from 300 nm through 650 nm, thus including the ultraviolet
but excluding the red portion of the spectrum. Other insects, such as butterflies, are also able to
see UV.
Experiments performed by Karl von Frisch (the Nobel Laureate animal behaviorist) showed that
honeybees are unable to distinguish between a red card and a gray one of similar tone, thus demonstrating that they are color blind for true red. Other such experiments show that a bee's vision within
the visible spectrum differs from ours in that they can discriminate between orange, yellow, and green
just as we can, but these colors appear more similar to them than they do to us. However, their ability
to discriminate between subtle differences in hue in the purple-violet and ultraviolet portions at the
lower end of the spectrum is much better than ours. In addition, bees can see two other colors: "bee
purple" and "bee violet". These colors result from combining UV reflectance and blue, yielding bee
purple, and UV plus yellow to give bee violet. Unfortunately, we have no concept of what these
colors might be. See if you can imagine a color outside the range of the visible spectrum.
The majority of flowers that humans see as white are actually brightly colored to the bee's eye.
Many white flowers absorb UV and thus appear to the bee as the complementary color of UV— blue-
green. In an alpine meadow, where there seems to be a plethora of similar purple, white, and yellow
flowers, the bees actually see a great diversity of colors. This allows them to distinguish between
different species which may be in flower at the same time.
*Helen Kennedy, Research Associate, Harold L. Lyon Arboretum, The University of Hawaii, 3860 Manoa Road, Honolulu,
Hawaii 96822.
**Fred R. Ganders, Department of Botany, The University of British Columbia, Vancouver, B.C.
1 Since humans cannot see UV, we must resort to photographic means to observe and record UV patterns on flowers. Black and white photographic film is sensitive to UV radiation. However, the
optical glass used in camera lenses is opaque to most of the UV and therefore a special fused quartz
lens which transmits UV has to be used. The transmitted UV radiation exposes the film and the image
is recorded. However, even with a quartz lens the amount of UV radiation entering the camera is
quite small compared to the amount of visible light. If the film is exposed primarily by visible light,
the UV pattern will be undetectable. So, a filter has to be used which transmits UV but blocks out
nearly all of the visible spectrum. The amount of light reaching the film through the filter is greatly
decreased, therefore either a very long exposure time or a very strong light source is necessary. Long
exposure times are impractical in the field since the slightest movement of the flower gives a blurred
image. The high intensity light produced by the electronic flash allows both a short exposure time and
a moderate depth of field.
The greatest problem in UV photography is focussing, because the focal length of UV differs from
that of visible light. In addition, you cannot see the object you are trying to focus when the filter is in
place. Therefore, it is necessary to determine the difference in focal length of UV relative to visible
light, focus with the visible, measure the distance from the flower to the lens, replace the filter, move
the camera to the calculated distance for UV, and then take the picture. The film is developed and
printed in the standard way. In a positive print, the areas reflecting UV are light colored or white
while absorbing areas appear dark. It should be noted that the photograph does not show what the
flower "looks like" to the bee, since the bee sees a combination of the ultraviolet pattern and the
pattern or color from the visible spectrum.
An ultraviolet pattern found in a large number of flowers consists of a dark (UV absorbing) centre
in an otherwise UV reflecting flower. The Spring Beauty Claytonia sibirica (Figure 1) is common in
woods and clearings in British Columbia, and has white or pinkish petals with darker pink veining.
The pink veins are visible nectar guides, but superimposed on the visible color pattern is a dark UV
absorbing centre. The pink lines point the way, and the dark centre marks the spot for the nectar-
seeking insect.
FIGURE 1. Claytonia sibirica (Portulacaceae) photographed in visible light (left) and in UV light (right). Note
the dark UV absorbing centre. FIGURE 2. Monoptilon bellioides (Asteraceae) photographed in visible light (left) and in UV light (right). Note
the dark UV absorbing disk flowers and UV reflecting ray flowers.
FIGURE 3. Lasthenia chrysostoma (Asteraceae) photographed in visible light (left) and in UV light (right). FIGURE 4. Collinsia parviflora (Scrophulariaceae)
photographed in visible light (top) and in UV light
(bottom). The lower lip is blue and the upper one is
magenta in visible light.
FIGURE 5. A pure white "albino" flower of
Collinsia parviflora photographed in visible light
(top) and in UV light (bottom). Note that the UV
pattern is the same as that shown by the normal blue
and magenta colored flowers. Members of the Asteraceae, such as the daisies, sunflowers, and dandelions, have flower heads
composed of many separate small flowers. The ray flowers around the perimeter of the head simulate
the petals of an ordinary single flower, and functionally the whole inflorescence is equivalent to a
single flower. The inflorescences of such flowers frequently show UV patterns. A dark UV absorbing
centre is a common pattern, just as in single flowers of plants of other families. In the Asteraceae, of
course, several central disk flowers make up the absorbing centre of the inflorescence, while the ray
flowers may reflect UV, as in the Desert Star, Monoptilon bellioides, a tiny annual of the Mojave and
Colorado Deserts of California (Figure 2).
A more spectacular pattern is found in the inflorescence of Goldfields, Lasthenia chrysostoma, a
golden-yellow daisy that carpets thousands of hectares of California grassland in spring (Figure 3).
Both disk and ray flowers are golden yellow, although the ray flowers are slightly lighter at the tips.
The central disk flowers and most of each ray flower absorb UV strongly, and only the tips of the ray
flowers reflect UV. There are thousands of species in the Asteraceae, and several different
yellow-flowered species are commonly found flowering together, even in lawns. Although they may
all appear very similar to human eyes, their UV absorption patterns may differ so that they are easily
distinguishable to pollinating insects.
Flowers which are bilaterally symmetrical frequently show asymmetric UV patterns rather than UV
absorbing centres. A good example is Small-flowered Blue-eyed-Mary, Collinsia parviflora. This is a
common spring flower on Vancouver Island and usually has a blue lower lip with the upper lip
magenta, or sometimes blue and white. The petals of the upper lip absorb UV; the petals of the lower
lip reflect (Figure 4). In Collinsia, the blue and magenta flower colors are due to anthocyanin pigments in the cells. Anthocyanins not only absorb in the visible spectrum but also in the ultraviolet.
However, the difference in UV absorption in the upper and lower lips is due not to different anthocyanins, but to other pigments. This is revealed in a pure white flowered mutant Collinsia which we
found at Mt. Douglas Park near Victoria, and which produces no anthocyanins at all. Surprisingly,
the pure white flowers show the same UV pattern as the colored flowers (Figure 5).
FIGURE 6. Langloisia matthewsii (Polemoniaceae) photographed in visible light (left) and in UV light (right). FIGURE 7. Camissonia sp. (Onagraceae) photographed in visible light (left) and in UV light (right). Note that
the corolla absorbs UV and is dark, while the anthers and pollen reflect UV and appear light.
6
Langloisia matthewsii, a tiny desert annual in the Phlox family, has especially pretty nectar guides.
The petals are pale pink, and the upper three display a pattern of dark maroon and white spots. But
the pattern of the nectar guide is actually more complex since the visible blotches are superimposed
on dark UV absorbing regions at the bases of these upper petals (Figure 6). The bold pattern leads the
insect to the nectariferous throat of the flower.
Not all UV patterns are, strictly speaking, nectar guides. Some yellow day-flowering species of
Camissonia (Evening-primrose) are pollinated by pollen-collecting bees, whose larvae are dependent
on Camissonia pollen for food. Since the bees visit the flowers for pollen, not nectar, it is not
surprising to find that there are no UV patterns on the petals. The entire corolla absorbs UV. However, the anthers and pollen reflect UV and therefore stand out conspicuously against the contrasting
color of the flower (Figure 7).
There is no fundamental difference between the visible and invisible patterns of flowers. Together
they make up the colors of the flower; the only difference is that we cannot see the entire pattern in
many cases. These floral patterns are part of a co-evolved system involving the structure of the
flowers and the behavior of the pollinators, and results in benefits to both plant and animal.
Once an insect learns where the nectar is located in a particular kind of flower in reference to the
pattern of colors and shapes, it can find the nectar more quickly when it visits the next flower. The
pattern also allows the insect to distinguish different species, and to specialize on one species in each
foraging flight. Such specialization is called flower constancy, and is most highly developed in bees.
The result is efficiency not unlike an assembly line. The insect can feed on more flowers per hour,
getting the greatest reward for the least effort. It is also to the plant's advantage to have an efficient
pollinator, since more flower visits mean more pollination and greater seed set in the population.
Pollinators that exhibit flower constancy also ensure that pollen is carried to other flowers of the
same species, so that the right kind of pollen reaches the right flower. Flower patterns and pollinator
foraging behavior present a classic case of mutualism, which benefits both partners. Graphica Botanica
In February the Graduate Students Association of the UBC Department of Botany held a Graphica
Botanica contest. We have great pleasure in printing the winning entries in two of the categories, line
drawings, and black and white photographs.
A. Line Drawings
First Prize:
'Poppy Capsule' Deborah Donaldson
Pencil on matte acetate Joint Second Prize:
'Gingko biloba' Deborah Donaldson
Pen and ink
8
VpasH-X*0^ "*2> Joint Second Prize:
'Beans' Joan Miller
Pen and ink
9
Joint Third Prize:
'A Saxifrage' Joan Miller
Pen and ink 10
Joint Third Prize:
'Privet' Deborah Donaldson
Pencil on matte acetate B. Black and white photographs
11
First Prize:
'Pumpkin cv. Spookie'
Lindsay Brooke
Taken with a Rolleiflex 35 mm camera
using a 50 mm lens and Tri-X film.
The photograph was taken on  a
kitchen counter using a table lamp to
provide side lighting. 12
Second Prize:
'Magnolia Blossom' Michael Adam
Photographed   in   'The   Glades',   Surrey,
British Columbia, using a 35 mm reflex
camera with a 55 mm lens and Tri-X film.
Third Prize:
'Caucasian Cow Parsley, Heracleum
mantegazzianum' Allen Banner
Photographed in The B.C. Native Garden
of The UBC Botanical Garden, using a
Zenith-B 35 mm SLR camera with a 58 mm
lens and Ilford FP4 film. The Genus Plectritis in British Columbia
Member of the Family Valerianaceae
PLECTRITIS BRACHYSTEMON Fischer & Meyer
Pale Plectritis
PLECTRITIS CONGESTA (Lindley) A. P. de Candolle
Rosy Plectritis or Sea Blush
PLECTRITIS MACROCERA Torrey & Gray
Longhorn Plectritis
Natural Distribution and Habitat
The genus Plectritis contains four species of annual herbs native to the Pacific Coast of North
America and one species in Chile. Three of the species occur in British Columbia.
Plectritis brachystemon is present in brushy but relatively open damp montane or lowland areas
below 1375 m, from British Columbia south to Monterey County in California. In British Columbia
it occurs in relatively open areas at low levels west of the Cascade Mountains on Vancouver Island,
the Sechelt Peninsula, and the Lower Mainland. It reaches its northern limit of distribution on the
Queen Charlotte Islands. Calder and Taylor (1968) believe that two populations on the west coast of
Moresby Island are the result of introductions by the Haidas from villages along the eastern shores of
Skidegate Inlet where the species is common.
Plectritis congesta is present at low elevations on open vernally moist slopes and meadows, on
ledges and among rocks, and in open woodland glades from British Columbia south along the coast
to San Luis Obispo County in California, rarely extending east of the Cascade Mountains. In British
Columbia it is abundant on rock ledges (especially above the sea) and on short-turf meadows on
Vancouver Island, the Gulf Islands, and the Lower Mainland, reaching its northern limit of distribution near Campbell River on Vancouver Island, and extending inland as far as the Cascade Mountains. Plants from the Queen Charlotte Islands are all referable to Plectritis brachystemon, not
P. congesta.
Plectritis macrocera is widespread in vernally moist open habitats between sea level and about
1220 m, from southern British Columbia south to southern California and east to Montana and Utah.
It is present in the Ponderosa Pine community in the dry interior areas of southern British Columbia,
reaching as far west as Yale in the Fraser Canyon. It is often found on open dry rocky sites but also
occurs in moister areas.
Description of the genus
The genus consists of annual herbs with an erect to sprawling stem which is either simple or with a
few paired axillary branches. The stem is usually slender, subglabrous or glabrous, but often with
tufts of hairs at the nodes.-
The roots are usually short, thin and fibrous. They, and other parts of the plant, have a characteristic odor somewhat reminiscent of parsnips, which is caused by the presence of valeric and isovaleric
acid. These terpenes are well known in the Valerianaceae.
The leaves are opposite, simple, entire or obscurely toothed near the base, and are either sessile or
short-petiolate. The lower leaves are obovate-oblong with a short petiole, whereas the upper leaves
are oblong or linear and sessile. There are no stipules.
13 The inflorescence is a subcapitate or capitate to interrupted-spicate cluster of several to many
flowers, subtended by linear-subulate bracts. Several of the bracts are fused at the base giving a
palmate appearance. The calyx is obsolete. The corolla is white to deep pink, occasionally with dark
red spots near the base of the midventral lobe. The five petals are united for most of their length to
form a 2-lipped or subequal 5-lobed subcampanulate to narrowly funnelform tube. There is usually a
broad spur, although this may be reduced to a swelling on one side of the base (gibbous). There are 3
stamens which are epipetalous (alternating with the corolla lobes) and exserted to included. The
stigma is 2-lobed (rarely 3-lobed), and flat-reniform. The ovary is inferior and 1-celled.
There is extreme variation in the fruits. In general, the fruit is a winged or wingless, dry, indehiscent
achene which is is whitish or pale straw-yellow to dark red-brown in color. The achene may be verni-
cose to dull, is usually more or less pubescent, and dorsally keeled. The wings, if present, are paired,
connivent or spreading, and occasionally have glands on their dorsal surface. The wings are formed
as an outgrowth from the dorsal angles of the fruit.
The presence of wings on the fruit is controlled by a single dominant gene. Almost all populations
of Plectritis congesta contain both winged and wingless fruited plants, but populations of P. brachystemon usually consist of only one form. On southern Vancouver Island, P. brachystemon is wingless,
but from Little Qualicum Falls northward and on the west coast of Vancouver Island, populations
have winged fruits. Mixed populations occur on the Lower Mainland and Sechelt Peninsula (Ganders
et al., 1977a, 1977b).
Key to separate the species in British Columbia
Corolla 5-9 mm long, bright to pale pink, infrequently white Plectritis congesta
Corolla 2-4 mm long, white to very pale pink.
_L ^~t Vancouver Island, Queen Charlotte Islands, Sechelt Peninsula and the Lower Mainland; achenes more or less
sharply keeled, keel not normally grooved, winged or wingless, wings with thin and scarious margin, hairs
when present thin and pointed Plectritis brachystemon
Interior of British Columbia, Fraser Canyon eastward; achenes with rounded or obtusely angled keel, often with
a dorsal groove, winged or wingless, wings with a thick margin Plectritis macrocera
Description of the species in British Columbia
Plectritis brachystemon—stems slender to rather stout, 10-60 cm tall, usually simple but sometimes
branched, and glabrous or nearly so. The leaves are l-5(-6) cm long, and the upper leaves are acute.
The inflorescence is densely capitate to densely verticillate-spiciform, 0.6-1.5 cm across, usually
terminal, and appears in February to June in British Columbia. The corolla is white to very pale pink,
1-3.5 mm long, tubular-funnelform, strongly bilabiate, and often spurless. The achenes are yellow-
brown to brown, 2-4.5 mm long, glabrous or pubescent, and 3-angled.
Plectritis congesta—stems slender to rather stout, angled, (2.5-)10-60 cm tall, usually simple but
sometimes branched, and glabrous or nearly so. The leaves are l-5(-6) cm long, 3-22 mm wide, 3 to 4
pairs per stem, and often slightly succulent. The lower leaves are spatulate or obovate and short-
petioled, the upper leaves are more oblong or elliptic and either sessile or amplexicaule. The inflorescence is densely capitate to densely verticillate-spiciform, 1.5-3.0 cm across, usually terminal, and
appearing in March to June in British Columbia. The bracts are slightly glandular-ciliate. The corolla
is subcampanulate and strongly bilabiate with 2 vertical lobes and 3 larger spreading horizontal ones.
There is a well-developed thick basal spur which is usually less than one-third the length of the corolla
tube. The anthers are bluish in color until they dehisce to expose the yellow pollen. The achenes are
pale yellow to brown, 2-4.5 mm long, and pubescent to glabrous. The hairs, when present, are
gradually and evenly attenuated to a thin point, and are long and flexible. The cotyledons are transverse to the ventral surface of the fruit. Cx7.0
A x 0.45
15
FIGURE 8. Plectritis congesta. A. Habit, B. flower, C. achenes, showing some of the variation found in the
species. 16
Plectritis macrocera—stems slender to rather stout,
10-65 cm tall, and glabrous or nearly so, although there
are often tufts of hairs at the nodes and the inflorescence
is often finely glandular-pubescent. The leaves are
1-4.5 cm long, 3-18 mm wide, glabrous, and diminish in
size upwards. The lower leaves are more or less obovate
and short-petioled, whereas the upper leaves are obovate
to ovate or linear or elliptic, often remotely serrate towards the base, and sessile. The inflorescence is capitate
(especially in small specimens) to interruptedly spicate
or 2-3-verticillate, appearing terete in life, and appear in
March to June in British Columbia. The bracts are
glabrous or glandular-pubescent. The corolla is
subcampanulate to broadly tubular, mostly white to
pale pink, 2-3.5(-6) mm long, and is usually regularly 5-
lobed to weakly bilabiate. There is a well-developed and
relatively long thick basal spur which is usually one to
two times the length of the corolla tube, and often
rather abruptly narrowed at about the middle. The
achenes are pale straw-yellow to red-brown, 2-4 mm
long, and pubescent to glabrous. The hairs, when
present, are clavate or long-cylindrical or long and curly,
blunt and stout. The cotyledons are parallel to the
ventral surface of the fruit.
Propagation
The seeds ripen in June or July when they fall to the
ground and lie dormant until September when they
germinate and grow to a 2- or 4-leaved stage. They overwinter in this form until early spring when they resume
growth as soon as the weather begins to warm up. The
Botanical Garden propagator has sown the seed in John
Innes Seed Mix in October with a high success rate.
They were then planted outside in early spring while
small. It may also be possible to sow the seed in January
or February with success. The seed could be sown broadcast outside where wanted—but in this case fall sowing
may lead to competition from other seedlings. The
plants growing in the Native Garden section of The
Botanical Garden have re-seeded themselves rampantly.
Transplanting
The plants may be moved easily when small, although
it is not usual to transplant annuals at any period other
than the seedling stage.
Conditions for Cultivation
The plants will grow in any soil from clay to good
garden soil as long as there is ample moisture in the
spring. They prefer open sunny positions when they will
form a solid mat of color covering the ground.
FIGURE 9. Plectritis brachystemon, x 0.55.
Note the smaller and less congested inflorescence of this species as compared to that
of P. congesta. Landscape Value
Plectritis species are excellent plants to grow in the ordinary garden because they form mats of
color early in the spring before most other plants are growing. They dry up to bare stems and seed
pods when flowering has finished—but by this time other annuals will have grown large enough to
hide them. Plectritis congesta is the most attractive of the three native species, as P. brachystemon
and P. macrocera are both rather drab in color.
Availability
Apparently not available from major seed catalogues. Therefore, the only way to obtain these
plants is to collect the seed in the wild initially, after this they will produce abundant seed in the
garden.
Varieties and Ornamental Cultivars
Plectritis is a difficult genus because there is close resemblance in general appearance among the
species, and also because each species shows a wide range of variation. This wide variation has led to
the proposal of a number of species based on inconstant variations in technical features of the flowers
and fruits.
Morey (1959) reduced P. brachystemon to a subspecies of P. congesta, and this treatment was followed by Taylor and MacBryde (1977). Recent work by Dr. Fred R. Ganders of UBC and his students
(Ganders et al, Wild., 1977b), has led them to believe that there are actually two separate species. The
flowers are morphologically distinct, they will not hybridize either in the wild or in the laboratory,
and biochemical experiments have shown that the two entities have quite different isozymes.
Plectritis macrocera is represented in British Columbia by the subspecies grayi (Suksdorf) Morey.
This subspecies differs from the type in that the flowers tend to be smaller (although this is not
constant) and the wings of the fruit are thin and scarcely grooved on the margin. The opening
between the wings on the concave side of the fruit is as long as or longer than wide (it is wider than 17
long in the type). The achene has a median longitudinal ridge on the ventral surface which usually
bears a multiseriate row of clavate or cylindrical bristles.
Specimens of Plectritis brachystemon and P. macrocera subsp. grayi are quite similar and are often
misidentified. In British Columbia, their geographical distribution is probably the easiest means of
identifying the two species—P. brachystemon is strictly coastal whereas P. macrocera subsp. grayi is
only present in the Interior of the Province.
Diseases and Problems of Cultivation
We have experienced few problems with the native species of Plectritis. They do seed readily and
spread widely, so that plants growing outside the desired area have to be weeded out. The only
problem in the Native Garden component has been with slugs which like these plants. There have
been no apparent insect or disease problems. However, Dr. Ganders reports that plants in the greenhouse and in growth chambers are attacked voraciously by aphids and are susceptible to mildew. He
has also seen wild populations in which the plants were infected with Rust.
Origin of the Name
The generic name Plectritis is believed to be derived from the Greek plektos or plectos, meaning
'plaited' or 'twisted', referring presumably to the complex inflorescence. The specific name brachystemon is derived from two Greek words—brachys, 'short', and sterna (or stemori), 'stamen'—combined to mean 'short stamens'. The specific eptithet congesta means 'arranged very closely together'
or 'congested', referring to the inflorescence. The specific name macroceras is also derived from two
Greek words, makros (or macros) meaning 'large' and keras (or ceras) meaning 'spur' or 'horn',
referring to the relatively large spur on the corolla. The subspecific epithet grayi is a commemorative
name honoring Asa Gray who was a Professor of Botany at Harvard University and a well-known
North American botanist in the nineteenth century. 18
The type locality of Plectritis brachystemon is "propre coloniam Ross in California" and is
believed to be in Sonoma County. The type locality of P. congesta is "on the north-west coast of
America'! It was originally described from horticultural specimens grown from seed collected by
David Douglas. The type locality of Plectritis macrocera is "California" where it was collected by
David Douglas. Plectritis macrocera subsp. grayi is presumed by most authors to be described from a
Suksdorf collection from Klickitat County in Washington, although Suksdorf himself apparently
cited two collections, one by W. C. Cusick from "Wasco County, Oregon" and one by V Rattan
from "California'!
... the rural appearance... [of Protection Island,
in "Juan de Fuca 's Straights'] strongly invited us
to stretch our limbs after our long confined
situation on board & the dreary sameness of a
tedious voyage. . . We found on landing. . . the shore
was skirted with long grass & a variety of wild
flowers in full bloom, but what chiefly dazzled our
eyes. . . was a small species of wild Valerian [now
known as Plectritis or Valerianella congesta/ with
reddish colored flowers growing behind the beach in
large thick patches.
Archibald Menzies, naturalist
with Captain George Vancouver,
1792. (From: Clark, 1973)
REFERENCES
Abrams, L. and R. S. Ferris. 1960. Illustrated Flora of the Pacific States. Vol. IV. Bignoniaceae to Compositae. Stanford
University Press, Stanford.
Calder, J. A. and R. L. Taylor. 1968. Flora of the Queen Charlotte Islands. Part 1. Systematics of the Vascular Plants. Monograph No. 4, Part 1. Research Branch, Canada Department of Agriculture, Ottawa. Queen's Printer, Ottawa.
Clark, L. J. 1973. Wild Flowers of British Columbia. Gray's Publishing Ltd., Sidney, B.C.
Davis, R. J. 1952. Flora of Idaho. Brigham Young University Press, Provo, Utah.
Ganders, E R., K. Carey and A. J. E Griffiths. 1977a. Outcrossing rates in natural populations of Plectritis brachystemon
(Valerianaceae). Canad. J. Bot. 55:2070-2074.
Ganders, E R., K. Carey and A. J. F. Griffiths. 1977b. Natural Selection for a Fruit Dimorphism in Plectritis congesta
(Valerianaceae). Evolution 31:873-881.
Hitchcock, C. L. et al. 1959. Vascular Plants of the Pacific Northwest. Part 4. Ericaceae through Campanulaceae. University
of Washington Press, Seattle.
Lyons, C. P. 1965. Rev. ed. Trees, Shrubs and Flowers to Know in British Columbia. J. M. Dent & Sons (Canada) Ltd.,
Vancouver.
Morey, D. H. 1959. Changes in nomenclature in the genus Plectritis. Contr. Dudley Herb. 5:119-121.
Munz, P. A. and D. A. Keck. 1973. A California Flora and Supplement. (Combined edition). University of California Press,
Berkeley.
Smith, A. W. 1972. A Gardener's Dictionary of Plant Names. Revised and enlarged by W. T. Stearn. Cassell & Co., Ltd.,
London.
Taylor, R. L. and B. MacBryde. 1977. Vascular Plants of British Columbia: A descriptive resource inventory. Technical Bulletin
No. 4. The Botanical Garden of The University of British Columbia. University of British Columbia Press, Vancouver, B.C. Botanical Garden News and Notes
Publications—The Botanical Garden is pleased to announce that the following publications are
now available:
Gardening as Therapy (Summer Season) is the second in the four part series designed to provide
expert guidance to persons working with handicapped people who wish to develop a program
using plants for therapy. The book is also useful for school programs in horticulture. Details on
the two books so far published in the series are available by writing to The Botanical Garden.
Plantae Occidentalis: 200 Years of Botanical Art in British Columbia is a 136-page book designed
to accompany the Exhibition of 109 works which opens at the Museum of Anthropology at the
University of British Columbia on April 17, 1979 for the summer, followed by tour stops at
Ottawa, Winnipeg and Calgary before returning to Vancouver. The book details the development
of Botanical Art in British Columbia from both the historical and contemporary point of view, is
lavishly illustrated in color, and has an extensive series of ethnobotanical commentary on the
plants depicted. This book stands on its own without the Exhibition, and will be a valuable asset
to people interested in Canadiana and in British Columbia in particular.
Phenology of Cultivated Rhododendrons in The Lower Mainland of British Columbia is the result
of a three-year study on flowering characteristics of cultivated Rhododendrons which has been
compiled by Dr. L. Keith Wade. This publication is designed to serve as a principle resource for
any Rhododendron enthusiast and for the horticultural nursery trades. The initial distribution of
the book will be at the 1979 Annual Meeting of the American Rhododendron Society to be held
in Vancouver in May 1979, but copies are for sale directly from The Botanical Garden Office.
1977 Annual Report from The Botanical Garden has now been printed. Limited copies are available by writing to The Botanical Garden.
New Distribution of Plants Initiated—The Botanical Garden in co-operation with the B.C. Nursery
Trades Association and through the auspices of the B.C. Landscape Plant Improvement Association
have issued a list of 21 introductions to the trade. These plants have come from various sources, and
have been tested and evaluated in The Botanical Garden for several years. A complete list of these
introductions is available either from The Botanical Garden Office or from the Secretary of the
British Columbia Landscape Plant Improvement Association, Mr. Ken Wilson of The Botanical
Garden. Distribution will be handled by the BCLPIA to members of the BCLPIA.
Completion of New Propagation Facility—-The new special facility for propagation and development
of new research materials has been completed and is now in operation at The Botanical Garden. The
new propagation unit contains 416 m2 of growing space, and will enable the Garden to become more
active in the development of new materials for The Botanical Garden and in the propagation of new
plant introductions for the industry. Research projects of members of University departments will
also use the new space. The building was designed in cooperation with The Botanical Garden by the
firm of Downs and Archambault of Vancouver, and was constructed by B.C. Greenhouse Builders
Ltd., Burnaby, B.C.
Audio-Visual Programs Available—The Botanical Garden in cooperation with the Biomedical Communications Centre of the University has produced an 11-minute slide/tape presentation entitled
"Plants and People". This program is designed to provide interest and stimulation for the severely
handicapped person working in horticulture. Distribution of this A/V slide/tape presentation can be
arranged by contacting either The Botanical Garden Office or Biomedical Communications of the
P.A. Woodward Instructional Resource Centre at UBC. The program was supported by financial
assistance from The P.A. Woodward Foundation.
A new A/V Slide Presentation has been completed on the Flora of British Columbia, with special
emphasis on the plants of the B.C. Native Garden in The Botanical Garden. This 30-minute slide
19 20
presentation gives impressions through the seasons of the plants growing in the B.C. Native Garden,
and may be made available on request to The Botanical Garden. The program was developed by The
Alpine Garden Club of British Columbia and the 'Friends of the Garden' Program at The Botanical
Garden. The initial showing was at the recent Study Weekend sponsored by The Alpine Garden Club
of British Columbia.
Educational Activities—Forthcoming activities at The Botanical Garden will include participation in
the Senior Citizen Education Program offered during the summer by the University of British
Columbia. This special program provides horticultural training to senior citizens, free of charge, at
the University.
The Vancouver Home and Garden Show—This show was held at the Pacific National Exhibition
buildings from February 23 to March 3, 1979, and was a resounding success for The Botanical
Garden. There was a major display covering 130 m2, plus educational talk presentations given by
Margaret Coxon and David Tarrant. An attendance of 81,950 at the Show ensured a wide distribution
of information about The UBC Botanical Garden.
Hortitherapy—The Hortitherapy Program has continued to grow and develop. Talks were given
during the month of March to the Kelowna Horticultural Society, Cottonwood's Extended Care
Hospital in Kelowna, the Multiple Sclerosis Society of Kelowna, and to The Seattle Garden Club. It is
anticipated that additional programs in hortitherapy will be continued with the Harry V Purdy
Extended Care Hospital at UBC, and activity continued at Pearson Hospital in the city of Vancouver.
Expert advice has been given to a number of other hospitals. The Banfield Pavilion of The Vancouver
General Hospital has recently erected a new octagonal hortitherapy greenhouse modelled after the
prototype at The Botanical Garden. Members of The Seattle Garden Club recently visited the Garden
to view the prototype of the hortitherapy greenhouse, and to discuss possible programs for The
Children's Orthopaedic Hospital in Seattle.
Index to Volumes 6-10 of Davidsonia—An index to volumes 6-10 of Davidsonia is being prepared
and will be issued in Spring 1980 with the first number of volume 11. An index to volumes 1-5 was
published with Davidsonia volume 5, number 4; copies of-this index are still available and may be
obtained from The Botanical Garden Office.
Climatological Summary1
Data                                                        1979
JANUARY
FEBRUARY
MARCH
Average maximum temperature
3.4°C
6.3 °C
10.8°C
Average minimum temperature
-2.3 °C
1.1 °C
4.0 °C
Highest maximum temperature
8.5 °C
9.2 °C
15.4 °C
Lowest minimum temperature
-9.6 °C
-4.2 °C
0.4 °C
Lowest grass minimum temperature
-13.2°C
-7.4 °C
-5.0°C
Rainfall/no. days with rain
56.7 mm/13
133.2mm/19
61.8 mm/10
Total rainfall since January 1, 1979
56.7 mm
189.9 mm
251.7 mm
Snowfall/no. days with snowfall
3.0 cm/3
4.6 cm/1
0
Total snowfall since October 1,1978
5.0 cm
9.6 cm
9.6 cm
Hours bright sunshine/possible
92.2/265.3
74.7/278.2
182.1/361.1
Ave. daily sunshine/no days total overcast
3.0hr/12
2.7hr/12
5.9hr/4
*Site: The University of British Columbia, Vancouver, B.C., Canada V6T1W5
Position: lat. 49° I5'29"N; long. 123° 14'58" W. Elevation: 104.4m A pink-flowered Manzanita, Arctostaphylos
sp., from the Mount Shasta region of northern
California, x 1.0.
Editorial Board
Fred R. Ganders, Vancouver, British Columbia. (Reproductive Biology)
Arthur R. Kruckeberg, Seattle, Washington. (Systematics, Evolution)
Gerald A. Mulligan, Ottawa, Ontario. (Cytology, Weed Science)
Frances Perry, Enfield, Middlesex, England. (Horticulture)
Douglas B. O. Savile, Ottawa, Ontario. (Mycology, Phytogeography)
Janet R. Stein, Vancouver, British Columbia. (Phycology)
Oscar Sziklai, Vancouver, British Columbia. (Forestry)
Nancy J. Turner, Victoria, British Columbia. (Ethnobotany) Prunus cerasiformis cv. Atropurpurea, Flowering Plum or Purple Plum, has pale pink flowers
in early April and purple leaves all summer. It
is a common garden and street tree in Vancouver. The fruits are purple, about 2.5 cm in
diameter, and are edible, but are only occasionally produced.
Volume 10
Number 1
DAVIDSONIA
Spring 1979
Contents
The Invisible Patterns of Flowers     1
Graphica Botanica 7
The Genus Plectritis in British Columbia 13
Botanical Garden News and Notes 19
Climatology 20

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