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Array DAVIDSONIA
VOLUME 4
NUMBER 1
Spring 1973 Cover
Flowering trusses of Rhododendron
macrophyllum, one of British
Columbia's rarest shrubs.
The common native Shooting Star,
Dodecatheon pulchellum, a welcome
harbinger of spring.
DAVIDSONIA
VOLUME 4 NUMBER 1
Spring 1973
Davidsonia is published quarterly by The Botanical Garden of The University of British
Columbia, Vancouver 8, British Columbia, Canada. Annual subscription, four dollars.
Single numbers, one dollar. All editorial matters or information concerning subscriptions
should be addressed to the Director of The Botanical Garden.
A cknowledgements
The cover drawing and plate of Rhododendron are by Mrs. Leslie Bohm, the vignettes
are by Mrs. Rosemary Burnham. Photographs of the ground orchids are by Dr. C. J.
Marchant. The article on Rhododendron macrophyllum was researched by Mrs. Sylvia
Taylor. Terrestrial Orchids of Europe
CHRISTOPHER J. MARCHANT
In the fall of 1972, The Botanical Garden of The University of British Columbia had the good fortune
to receive a donation of some hundred living plants of European ground orchids from Mr. M. Harbeck.
It is probably safe to say that the majority of plant lovers and even some botanists do not realize the
potential of the wild ground orchids of temperate regions. In one sense, in view of their rarity and susceptibility to vandalism, this is a good thing! In contrast to the flamboyant, exotic finery of the myriads
of tropical genera and species in cultivation, these diminutive terrestrial gems possess a delicate, pristine
beauty and a charm of an altogether different quality. Many of them display in miniature all the elaborate texture and coloration of their tropical counterparts and are distinctly worthy of pride of place in a
cool greenhouse or outdoor peat or scree garden.
While it is true that many terrestrial orchids are at their best in natural drifts among their native vegetation, vast variety in flower shape and coloration is seen clearly and at best only in the closeness of a
garden. Let us examine some of the variety of forms found within the group.
It should be recognized that much of the form of ground orchid flowers is dictated by their adaptations
to pollination. Natural selections and gene complexes have operated on the interactions of insect pollinator and floral organs to produce some staggering aids to pollination. A majority of species have markings
or shapes which act as direction indicators to the pollinating insects, guiding them to both the nectar
glands and the pollen and stigma. Examples of markings are the dots and lines on the labellum of
Anacamptis pyramidalis (Pyramid orchid) and Dactylorrhiza species.
In addition, there is a whole range of fascinating shapes in the labellums of various genera, and these
are often named after their resemblance to a familiar creature. Thus, we have the Lizard orchid, Himan-
toglossum hircinum, with extremely long filaments hanging from the dissected labellum; the Man orchid,
Aceras anthropophorum, with hooded "head" and proportioned "limbs " the Military orchid, Orchis
militaris, with pointed helmet; and, the Butterfly orchid, Platanthera bifolia.
One terrestrial orchid with particularly large flowers is the Tongue orchid, Serapias lingua. The flowers
are few, violet with green speckles, and surrounded by violet-red tinted bracts held firmly and elegantly
on the stems. From the front, the shape of the lower lip can be seen to give the flower its name.
In special cases, the forms and markings of the flower of a species, particularly of the lower lip or
labellum, are an exact imitation of the female of an indigenous insect which pollinates the particular
orchid species. The mimicry aided by flower scents is so exact that it attracts the male insect, which then
attempts to copulate with the pseudo-insect and in doing so effects pollination by triggering the flower
mechanism. Usually the orchid pollen contained in pollinia has structures which attach it to the insect's
head or mouth parts, enabling its transport to another flower, and subsequent release of pollen on to the
receptive female stigma. That evolution has been able to create such an elaborate mechanism is one of
the wonders and mysteries of the natural world. Best examples of these insect mimicry flowers are the bee
orchids and fly orchids. The most well-known in Europe are perhaps the bee orchids Ophrys apifera, O.
bertolonii and O. bombyliflora. Ophrys apifera is quite common but very erratic in appearance, some
years very numerous and others scarce. The flower has a brownish purple three-lobed lip with markings
and pink outer segments. It likes a sloping location which is wet in winter and dry in summer.  Above: Two unusual ground orchids from Europe: left, Aceras anthropophorum, the Man Orchid; and
right, Serapias vomeracea, the Long-lipped Serapias.
The second species, O. bertolonii, is rarer. It has a large black lower lip and clear pink outer segments
with green veining. It is a southern European species. Ophrys bombyliflora is a very rare species of the
southern Mediterranean region, North Africa, Greece and Crete. Its velvety black lower lip with pointed
lateral lobes is closely reminiscent of a bumble bee.
The Fly orchid, Ophrys muscifera, is the most remarkable, and also one of the most widespread of
European terrestrial orchids. The outer green and brown perianth segments stand out like limbs and antennae, while the velvety black to brown, blue-marked lower lip is distinctive. The effect is to give the
impression that each of the widely spread flowers on the spike contains a fly clinging closely and drinking
nectar.
There are a good many other European orchid genera, all of them attractive and delicate, often inconspicuous with thin small flowers. Among them are Cephalanthera, Epipactis, Gymnadenia, Coeloglos-
sum. The genera Spiranthes, Listera and Corallorhiza will be familiar to botanists of the Pacific Northwest, not forgetting Calypso bulbosa which, in Europe, inhabits cold marshes and woods of Norway,
Lapland and Northern Russia.
The majority of the group should grow well in the climate of British Columbia, and we hope they will
establish successfully in the new Alpine Garden at the University.
REFERENCES
Duperrex, A. 1961. Orchids of Europe. Translated by A. J. Huxley. Blandford Press, London.
Goulimis, C. N. and N. A. Goulandris. 1968. Wild Flowers of Greece. Edited by W. T. Stearn. The Goulandris
Botanical Museum, Kifissia, Greece.
Polunin, O. and A. Huxley. 1970. Flowers of the Mediterranean. Chatto and Windus, London.
Opposite: Some European orchids: upper left, Dactylorhiza occidenlalis; upper right, Dactylorhiza traun-
steineri, Traunsteiner's Orchid; lower left, Plantanthera cholorantha, the Greater Butterfly Orchid; and
lower right, Dactylorhiza sambucina X D. maculata, a cross between the Elderflowered Orchid and the
Spotted Orchid. Rhododendron macrophyllum D. Don ex G. Don
CALIFORNIA RHODODENDRON, CALIFORNIA ROSEBAY, WEST COAST
RHODODENDRON, PACIFIC RHODODENDRON, PACIFIC ROSEBAY
Member of the Family Ericaceae
Natural Distribution
Rhododendron macrophyllum occurs from coastal southern British Columbia southwards to northern
California, extending eastwards into the Cascade Mountains in Oregon. In British Columbia it is very
rare and occurs only locally in Manning Park, the Skagit Valley, near Hope and on Vancouver Island.
The shrub is at the northern limit of its range here.
Habitat
The habitat is characterized by cool summers and wet winters. Rhododendron macrophyllum is found
usually below 1500' in moist woods in the shade, and in ravines and openings in shady forests in areas
free from lime. In the Skagit Valley it occurs on dry gravelly sites in association with semi-open stands of
Douglas fir and lodgepole pine.
Description
An evergreen shrub, 3-10 (-26) feet tall with strong, stout stems and a shallow and fibrous root system. The bark is reddish-brown and scaly. Twigs are moderate to stout, puberulent when young, becoming
glabrous with age. Pith rather small, roundish, somewhat coloured, continuous.
Buds solitary and sessile, often clustered, with several to many imbricate scales, upper buds usually
ovoid, larger and the flower bud usually much enlarged, the lower buds successfully smaller and with
fewer exposed scales.
Leaf scars alternate, low, shield-shaped and often notched at the top or the lowest linear, bundle trace
1, round or crescent shaped.
Leaves are alternate or somewhat whorled, shiny dark green above, paler beneath, 8-20 cm long, up
to 6 cm broad, elliptic, acute at the base, apex obtuse or sharp pointed, entire, glabrous above, velvety-
puberulent beneath, thick and coriaceous, slightly to strongly inrolled along the margin, midrib prominent, tapering into the petiole. Petiole 1-2 cm long, stout.
Flowers during May and lune in British Columbia, April to luly in other parts of the range. The inflorescence is a terminal, umbel-like cluster with up to 20 showy flowers. Calyx is minute, very shallowly
5-lobed, bell-shaped. Corolla is tubular-campanulate, 2.5-4 cm long, 3-5 cm broad, slightly irregular, pale
pink to red to deep rose-purplish, occasionally white, upper lobes spotted red-brown inside, deeply 5-lobed,
the lobes spreading, crisped-undulate. Stamens 10, unequal, the longer ones about the same length as the
corolla and well-exserted, filaments sparsely pubescent or short hairy on the lower third to one-half.
Anthers oblong, red-brown to purplish, 2-3 mm long, opening by pores at the apex. Style reddish-purple,
as long as the corolla, stigma capitate or very shallowly lobed. Ovary 3 mm long, white silky hairy,
superior, 5-celled with many ovules. Pedicels glabrous, up to 5 cm long.
Fruit a dry woody capsule, 5-locular, 5-valved, 1.5-2 cm long, rusty-puberulent and glandular, calyx
persistent at the base. Seeds numerous, about 3 mm long, elongated, flat, wing-margined, brown, rather
scale-like, embryo minute and cylindric.
Propagation
Seed can be sown as soon as ripe in a cool greenhouse, or stored in an airtight container in a cool place
for up to a year. Spring sown seed may be germinated outdoors in a shady place. The seeds should be
sown in pans or boxes filled with sandy peat which has been well-watered. Cover the peat with a layer of
finely cut sphagnum, press down lightly and sow the seeds on top of the sphagnum. Place the seedlings in
a cool frame the following spring and gradually harden off.
Semi-ripe or hardwood cuttings should root easily, especially after using a root-promoting hormone.
Forms and varieties may be grafted on seedling understock of R. macrophyllum.
Transplantation
Easily transplanted with a good ball of soil around the roots in early spring or early fall may be satisfactorily planted later. All Rhododendrons are surface rooted, the top of the ball of soil should not be FIGURE 1. Rhododendron maerophyttum. A. Habit of shrub at flowering time, B. longitudinal cross-section of flower, C.
flowering truss and expanded vegetative bud, D. fruiting inflorescence. 6
more than 1" below the surface and care must be taken not to damage the feeding roots. Water thoroughly and apply a mulch.
Conditions for Cultivation
The shrub is slow-growing. The recommended hardiness zone in Canada is Zone 8. The shrub needs
a cool moist but well-drained acid soil in a position where it will be sheltered from long periods of hot
sun or winter winds, and a cool moist climate with plenty of atmospheric moisture. The ideal soil has a
pH 4.5-6.5 and contains plenty of humus. Permanent mulching with pine needles, peat moss, oak leaves
or other acidic substances is excellent—this keeps the ground cool and moist, and maintains the acidity
of the soil as the material decomposes. Water well just before the ground freezes in winter to ensure that
the shrub has sufficient water for the winter. Fertilize occasionally in early to mid-spring with well rotted
manure or a commercial fertilizer which leaves an acid residue in the soil. Ammonium sulphate is often
recommended but must be used with care because too much will quickly kill plant tissues and it should be
used only in the spring. Careful checking every two or three years of the pH of the soil, especially in
foundation planting near brick buildings or where there is a lot of exposed concrete, is necessary because
rain dissolves a certain amount of lime from these materials which then washes into the soil causing it to
become more alkaline. Aluminum sulphate is added to the soil in the correct amount as determined by
testing to correct this. Do not use a rake or hoe around the base of the shrub because of the shallow root
system—if weeds occur, pull out by hand or cut them off without disturbing the soil. Picking off dead
flower clusters as soon as they fade is good practice, though not absolutely necessary when the plant is
large. Pruning is generally restricted to the removal of dead or diseased branches, or of those that give
the plant an unbalanced appearance. Old plants may be encouraged to give good and vigorous growth by
a severe pruning early in spring before growth starts.
Landscape Value
Rhododendron macrophyllum belongs to a group of plants of great landscape value where growing
conditions are suitable, and it is regarded by many as the most handsome plant indigenous to the Pacific
Coast. As an evergreen species, it is attractive throughout the year with showy flowers and handsome
foliage. It is equally effective and desirable as a singe specimen or massed in a large group, although
it could become too large for the small garden. It can become rather leggy and the site in the garden
should be chosen with care. Like all rhododendrons, it is especially showy when backed by the dark.green
foliage of conifers, which also provides an ideal shelter. Especially useful for foundation plantings (but
see above section) or large mass shrub borders in milder areas. Rhododendron macrophyllum is probably
hardier and superior in other respects to many Asiatic species for cultivation west of the Cascades.
A vailability
There is no known commercial source in Canada.
Varieties and Ornamental Cultivars
The form with smaller white flowers, smaller capsules and larger, more pointed leaves is sometimes
distinguished as Rhododendron macrophyllum var. album. The Skagit Valley form appears to be drought
resistant and to resent over-watering but has not been named.
The cultivar 'Albert Close' of either R. maximum X R. macrophyllum or R. maximum X 'Mrs. lamie
Fraser' origin is of medium height with blue-green leaves and flowers rose-colored with dark throat markings in compact conical trusses. It is a late bloomer and heat-tolerant.
'Oregon Queen', an Azaleodendron representing a presumed natural hybrid between R. macrophyllum
and R. occidentale, was originally found in mountains of Oregon. This cultivar has unusually fine foliage
and beautiful pink and yellow flowers. An exceptional unnamed dwarf form is cultivated in the Portland
Test Garden. A double form found in woods near Fort Bragg, California has been propagated by lohn
Drueckers of Fort Bragg, who said he would call it 'macrophyllum fastuosum'. R. macrophyllum X R.
tephropeplum, apparently crossed by Ben Lancaster, gave a very interesting plant—leaves about half size
of macrophyllum with glossy texture of tephropeplum on a compact dwarfish plant that grows well in sun
or shade. Flowers orchid-pink in a neat 3Vi"-4" truss. Roots readily.
Other Uses
The genus possesses astringent narcotic properties, produces hard close-grained compact wood which is
sometimes used in turnery and for fuel. Seedlings of R. macrophyllum have been used as understock for
grafted plants. Diseases and Problems of Cultivation
Probably the most difficult problem is maintaining the necessary level of acidity in the soil, and testing
every two or three years is a sound idea. Chlorosis or leaf yellowing is common when the soil becomes too
alkaline or the shrub is planted too close to a cement wall. The plant is unable to absorb iron and thus
becomes chlorotic. Treat the soil, or as a temporary measure, spray the leaves with an iron chelate.
Many rhododendrons may be killed when strong cold winter winds follow warm days in early spring.
The damage may not be apparent until two or three weeks later when the leaves become brown, especially
at the edges and near the tips. It is caused by an excessive loss of water by the leaves at a time when the
roots are unable to obtain water from the soil. Can be prevented by growing the plants in a position where
they will be sheltered from strong winter winds.
Rhododendrons should not be planted near black walnut trees or they may suddenly wilt and die,
apparently due to toxins secreted by the roots of the walnut.
Occasionally woodpeckers may completely girdle stems up to 3" in diameter and the distal portion then
dies. No effective repellent has been developed.
Some wasps bite holes in the leaves and chew them to make paperlike nests but no control is suggested.
The best way to keep rhododendrons free of insects and disease is to provide good growing conditions.
Insects:
1) Brachyrhinus sulcatus and B. ovatus 'Black vine weevil' and 'strawberry weevil'—adults feed on the
leaves at night during spring and early summer cutting holes along the margins, sometimes devour the
whole leaf except the midvein and large veins. The larvae feed on the roots and bark at the junction of
the stem and root during the winter. If the stem is completely girdled by the larvae the plants will die,
plants not completely ringed are usually badly crippled, lose most of their leaves or fail to make normal
growth for several seasons or until a callus has formed over the damaged tissue.
Adult weevils can be killed by a foliage spray containing chlordane and the young forms by spraying
the soil around the base of the shrubs.
2) Stephanitis pyrioides and S. rhododendri 'Lace bugs'—black and white sucking insects which feed
on the undersides of the leaves. Their excreta appears as rather large brown sticky spots on the under side
of the leaves while the upper surface is marked by numerous whitish specks.
Spray the leaf undersurface as soon as the eggs hatch in May, and repeat in summer and fall if additional lace bugs appear.
3) Ramosia rhododendri 'Rhododendron borer'—the larva of a clearwing moth which bores into the
main stems leaving ugly scars and sometimes killing large branches.
Cut and destroy infected branches as soon as observed. Spray against the moths in May and June.
4) Giardomyia rhododendri 'Rhododendron tip midge'—newly developing leaves are rolled and their
edges browned by small white maggots. New growth is stunted.
Spray the growing tips.
5) Dialeurodes chittendeni 'Rhododendron whitefly'—causes yellowish mottling on the upper surface
of the leaves with a rolling of the margins. Young insects are greenish, almost transparent, very flat and
oval in shape and produce much "honeydew" which provides nourishment for Black Sooty Mold as a
secondary infection.
A 2% white oil emulsion has given good control in the Pacific Northwest, but it must be used only on
cloudy days to avoid injury to the plant.
Diseases:
1) Phytophthora cactorum 'Dieback'—the terminal buds and leaves turn brown and droop as though
in the winter condition. The stem shrivels and a canker is formed which encircles the twig, all parts above
the canker then die. The same fungus causes lilac twig blight; therefore, the two genera should be well
separated.
All diseased tips should be pruned out well below the infected parts and burned. Spray with fungicides
as new leaves emerge and repeat two weeks later.
2) Leaf spots are caused by at least 7 different fungi. Keeping the plants in good condition will help to
prevent the entrance of many of these.
3) Phytophthora cinnamomi 'Rhododendron wilt'—affects plants up to two or three years old, attacking roots and lower stems. The fungus thrives under high moisture conditions, high temperatures and less 8
acid conditions than rhododendrons prefer—destroy infected plants and adjust soil and general growing
conditions before replanting.
4) Armillaria mellea 'Shoestring root rot' or 'Honey mushroom'—affects many species of trees and
shrubs. Rarely attacks plants in good condition, ensure that the crown of the plant is exposed to the air
so that the bark is well dried.
H. N. W. Toms (1964) lists only two diseases which have been found on wild R. macrophyllum in
British Columbia—Chrysomyxa piperiana 'Rust' and Exobasidium vaccinii 'Red leaf.
The generic name is derived from the Greek words rhodon for a rose and dendron or dendros for a
tree. The name was first applied by the Ancient Greeks to the rose-flowered oleander (Nerium oleander)
but was later transferred to these woody plants by Linnaeus in 1753. The specific name macrophyllum
means with long or large leaves—the leaves were longer than any known at the time the original description was written. The type locality is "northwest coast of America" where it was collected by Archibald
Menzies near Port Discovery in 1792 during Captain Vancouver's voyage.
This species is sometimes referred to as R. californicum Hook, because Don described the plant collected by Menzies as having white flowers whereas Hooker's description had pink flowers. However,
there is only one Rhododendron on the West Coast to which the two names could apply so the earlier
R. macrophyllum is retained.
Rhododendron macrophyllum is on the list of plants protected by the British Columbia Provincial
Government and, therefore, the flowers cannot be picked, nor shrubs transplanted from the wild.
It is the State Flower of Washington.
As in many Ericaceae, the leaves contain a toxic substance which can kill livestock—they, however,
usually avoid these plants when other forage is available. It is also toxic to humans (Kingsbury 1964),
but there is some recent work which suggests that there might be a medicinal use for the toxic substance
for the relief of high blood pressure (Leach 1967). The honey of certain species of Ericaceae, including some Rhododendrons, is also reputed to be toxic to humans.
Two other rhododendrons are native to B.C.—R. albiflorum is found in mountains where it is common on shady moist slopes near the timberline; R. lapponicum is a dwarf arctic plant found on mountain
slopes in northern and northeastern B.C.
REFERENCES
Bowers, Clement Gray. 1968. Rhododendrons and Azaleas. (2nd edition). The MacMillan Co., New York.
The Canadian Skagit. In: Environmental Newsletter 7 (Aug. 1971). Issued by F. G. Slaney Co.
Garman, E. H. 1963. Pocket Guide to the Trees and Shrubs of British Columbia. (Rev. Ed.). British Columbia
Forest Service Publication B 28.
Gillett, J. M. 1971. The Native Rhododendrons of Canada and Alaska. Greenhouse—Garden—Grass 70:35-45.
Hitchcock, C. L. et al. 1959. Vascular Plants of the Pacific Northwest. Part 4. Ericaceae Through Campanula-
ceae. University of Washington Press, Seattle.
Leach, D. G. 1961. Rhododendrons of the World and How to Grow Them. Charles Scribner's Sons, New York.
Leach, D. B. 1967. Garden Journal 77:15-18, 33.
Pirone, P. P. 1970. Diseases and Pests of Ornamental Plants. (4th edition). Ronald Press Company, New York.
Quarterly Bulletins, American Rhododendron Society.
Rhododendrons for Your Garden. 1961. American Rhododendron Society. Portland, Oregon.
Sherk, Lawrence A. and Arthur R. Buckley. 1968. Ornamental Shrubs for Canada. Research Branch, Canada
Department of Agriculture. Publication   1286. Queen's Printer, Ottawa.
Smith, A. W. 1971. A Gardener's Dictionary of Plant Names. (Revised and enlarged by W. T. Steam). Cas-
sell, London.
Szczawinski, A. F. 1962. The Heather Family (Ericaceae) of British Columbia. Handbook #19. British Columbia Provincial Museum.
The Rhododendron Handbook. 1967. Part 1. Rhododendron Species in General Cultivation. Royal Horticultural
Society, London.
Toms, H. N. W. 1964. Plant Diseases of Southern British Columbia. A Host Index, p. 143-225. Reprinted from
Canadian Plant Diseases Survey. Volume 44. Canada Department of Agriculture Publication. Ottawa.
Van Veen, Ted. 1969. Rhododendrons in America. Sweeney, Krist & Dimm, Inc. Portland, Oregon, 97209.
Westcott, Cynthia. 1946. The Gardener's Bug Book: 1,000 Garden Pests and How to Control Them. The American Garden Guild, Inc. and Doubleday and Company, Inc., New York. Botanical Garden News and Notes
Alpine Garden Initiated—Tenders have been submitted and the contract let for the construction of the
Alpine Garden component of The Botanical Garden. This will involve the transportation of some 2,000
tons of rock from the interior of B.C., landscaping on the site and planting.
Presentation—At the April meeting of The Alpine Garden Club of B.C., The Botanical Garden was presented with a 40-year old specimen of the rare Thuja plicata 'filiformis' of local natural origin.
Local Initiatives Program—Under the government-sponsored Local Initiatives Program, a group of 14
men are currently employed in the development of the B.C. Native Garden on The Botanical Garden site.
The work includes scrub clearing, preparation of land and installation of plants.
Staff Activities—Three members of staff—Dr. Roy L. Taylor, Mr. Ken Wilson and Mr. David Tarrant—
attended the annual meetings of the A.A.B.G.A. in Arcadia, California—Dr. Taylor was elected Vice
President of the Association. In March, Dr. Taylor was elected President of the Biological Council of
Canada, an association of biological societies representing some 5500 Canadian scientists.
British Columbia Landscape Plant Improvement Association—The Botanical Garden is well represented
on the Board of Directors of the newly formed British Columbia Landscape Plant Improvement Association. Dr. John Neill is Vice President and Treasurer and Mr. Ken Wilson is Secretary. First task of the
Association has been to establish a mother block of virus-free flowering cherry varieties at the University.
These have been processed at the Canada Agriculture Plant Quarantine Station at Sidney, B.C., or have
been imported from Prosser, Washington and East Mailing. The organization has been set up on a nonprofit basis, proceeds from the sale of budwood to local nurserymen going toward maintenance of the
block. Some crabapple varieties have been included in the original planting. The Association, working
closely with The Botanical Garden, will expand its activities to the testing and introduction of new plant
material to the trade.
Botanical Garden Extension Programs—This spring The Botanical Garden continued its extension
courses, "Gardening Through the Seasons." In Series I, 6 classes covering topics of immediate interest to
the beginner attracted a total of 40 people. The Series II was extended to include two day-time courses
as well as one evening course. The subjects given included propagation, pruning and rock gardens. A
walking tour of the campus and a visit to a local nursery served as a visual means of the use and maintenance of plants in the garden. Practical demonstrations and some student participation were included
in most classes.
The course "Gardening for Apartment Dwellers" of 4 classes given at the Vancouver Public Library,
was extended to include a day-time course. A total of 232 registrants ascribes to its popularity and the need
to have plant material in close association with people who do not have traditional gardens.
The 1972-73 fall and spring gardening instructional program had a total of 378 participants.
9
CLIMATOLOGICAL SUMMARY
Data                                                          1973
January
February
March
Mean temperature
36.90°F
41.45°F
43.15°F
Highest temperature
53.0°F
58.0°F
53.0°F
Lowest temperature
17.0°F
27.0-F
32.0°F
Grass Minimum temperature
8.0°F
12.0°F
21.0°F
Total rainfall/No. days with rainfall
7.32V19
3.11"/12
3.00"/19
Total snowfall/No. days with snowfall
3.2"/3
nil
nil
Total hours bright sunshine/possible
60/265.39
88.2/278.24
107.7/361.16
Max. wind speed (m.p.h.) 1 hour/direction
20/SE
12/SE
15/SE
Mean mileage of wind at 3'
86.0
68.0
80.9
Mean mileage of wind at 40'
129.4
101.7
118.4
*Site: The University of British Columbia, Vancouver, B.C., Canada
Position: lat. 49°15'29"N; long. 123°14'58"W. Elevation: 342.6' Fritillaria lanceolata, the
Chocolate Lily, is another
harbinger of spring in
British Columbia.
DAVIDSONIA
Volume 4      Number 1 Spring 1973
Contents
Terrestrial Orchids of Europe    1
Rhododendron macrophyllum or Pacific Rhododendron    4
Botanical Garden News and Notes    9
Climatological Summary    9
VPRICE PRINTING LTD.

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