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Davidsonia Mar 1, 1975

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Array DAVIDSONIA
VOLUME 6
NUMBER 1
Spring 1975 Cover
Cyclamen orbiculatum var. coum,
a member of the Primrose Family
(Primulaceae). This hardy and
easily grown plant forms attractive
clumps when naturalized in the
garden.
Magnolia X soulangeana,
the Saucer Magnolia
DAVIDSONIA
VOLUME 6
NUMBER 1
Spring 1975
Davidsonia is published quarterly by The Botanical Garden of The University of British
Columbia, Vancouver, British Columbia, Canada V6T 1W5. Annual subscription, six
dollars. Single numbers, one dollar and fifty cents. All editorial matters or information
concerning subscriptions should be addressed to The Director of The Botanical Garden.
Acknowledgements
Pen and ink illustrations are by Mrs. Lesley Bohm. Photographs accompanying the feature
article are by Dr. C. J. Marchant; the map showing cliff erosion sites was prepared by Miss
Andrea Adamovich. The article on Dodecatheon was researched by Mrs. Sylvia Taylor and
Ms. Geraldine Guppy. Editorial and layout assistance was provided by Ms. Geraldine Guppy
and Mrs. Jean Marchant. Cliff Erosion Control with Plants
CHRISTOPHER J. MARCHANT
For at least half a century, perhaps several centuries, the 300 foot high sea cliffs at Point Grey
have been gradually eroding. Aerial photographs indicate this, and they also show that in recent
years an increasing area has been affected. It appears that there has always been a somewhat
cyclical variation in the vegetation cover, which has advanced and receded coincident with
fluctuation in cliff stability. However, this natural geological phenomenon has now become a
major cause for concern to the University of British Columbia, since parts of the university campus
sit strategically on the summit of the cliffs, and some of the land and large buildings (among them
the temporary headquarters of the Botanical Garden) may be threatened with eventual subsidence
into the ocean.
The geological structure of the cliffs consists of bedded and consolidated sands and gravels
overlying about 40 feet of clay deposits at the base. A subsequent thin layer of glacial till has been
deposited over the sands. Under natural and stable conditions the cliffs are clothed with a climax
vegetation of Coast Douglas Fir; there are also successional areas with Alnus rubra (Red Alder),
Thuja plicata (Western Red Cedar), and native shrubs.
Aerial photos indicate that erosion initiates mainly at the clay/sand interface, where natural
and seepage groundwater flows to the cliff face and causes undercutting of the sands. Subsequently,
on bare sites, wind and frost play their part. In addition the spring high tides wash against the base
of the cliffs and remove the accumulated sand fallen from above. It seems probable that under
natural conditions a given site would erode for a time, then heal over with new vegetation. This is
supported by evidence from aerial photography. However, in recent years two major changes have
come about. Firstly, buildings and paved areas have enormously increased and probably altered
the surface and subsurface drainage patterns. Secondly, the beach has become a very popular
recreation area and many people climb on the cliffs, opening up new erosion areas in stable
vegetation and dislodging tons of sand in eroded sites. This new biotic factor is interrupting the
natural vegetation regeneration cycle and hence erosion is now increasing unchecked.
The Botanical Garden at the University of British Columbia, with financing from a special grant
by the University, has initiated an experimental Cliff Erosion Control Scheme. This project, coordinated by myself and supported by two hired students, is designed to test selected native and
imported vegetation for suitability in recolonising the eroding areas and discouraging human access
to the cliff face. The scheme is intended as an integral part of the joint U.B.C./Provincial Government schemes to mechanically stabilise the cliff toe and cliff face and prevent further loss of
land area.
Planning and selection of the plant material for this project required recognition of the main
cliff geoclimatic and biological features affecting plant growth, some of which were discussed
above. These include:
(1) Mobile sand which is subject to extreme drying in rainless periods.
(2) Vertical upper faces, from which falling lenses of sand are deposited temporarily on
lower slopes.
(3) Active frost erosion in winter when the cliff faces are wet. FIGURE 1. Site 4 near the Museum
of Anthropology. Erosion here is
severe, and human activity too
great for a planting scheme to
succeed. Buttresses of clay indicate
the level of the basal sedimentary
clay layers.
(4) Active wind erosion in summer when the cliff faces are dry.
(5) Relatively dry upper slopes.
(6) Wet lower levels, especially the clay layers.
(7) Human disturbance of loose sand and vegetated areas.
Certain criteria were established with respect to the kinds of plant material selected, and also
in relation to the site, which is basically a northwest slope subject to periodic strong northwesterly
winds. Plant species suitable for revegetation should be fast-growing and easy to establish, salt-
spray and wind tolerant, able to withstand extremes of temperature and soil dryness, and tolerant
of mobile sand and periodic burying. They should also be able to bind the substrate by means of
deep-penetrating roots, creeping underground stems or other structures, and should have
characteristics which will discourage human interference, e.g., thorns, spines or a thicket-
forming habit.
An important requirement of the project is to maintain as far as possible the appearance of the
natural cliff vegetation. This does not necessarily confine experimentation to native material from
British Columbia. Indeed, it is the local vegetation which has shown inability to resist the present
erosive forces; for this reason, testing extends to non-native plant species from other temperate
regions.
It would be desirable to experiment with plants on the largest and most severe erosion site,
which lies between the cliff-top buildings of Cecil Green Park and the new Museum of Anthropology. However, we have begun by seeking smaller sites where the passage of people is less
severe and can be partly controlled. The accompanying map of the Point Grey Cliff shows the
eroding sites, and indicates how we have numbered them for ease of description.
The first site chosen (Site 1), near Searchlight Tower l,was artificially filled with subsoil but
after a few weeks was abandoned, owing to a severe washout during a period of heavy rain. The
experience there indicates the high risk of artificially rebuilding eroded cliff faces without careful
prior assessment and planning.
FIGURE 2. The natural vegetation
of the cliff face in its undisturbed
state. Note the abundant woody
plants and ferns. FIGURE 3. A map of the Point Grey cliffs showing the experimental revegetation sites.
Eroded areas are indicated by shading.
The second site (Site 6) is an isolated but fairly typical section of eroded cliff, west of Searchlight Tower 2. Aerial photos show that it has been eroded at least since 1956, and during the first
season of our work several collapses of the upper cliff were seen to occur. At the top of Site 6 a
30-foot vertical cliff exposes the bedded sand strata of the region. Below is a 150-foot wide steep
slope of mobile sand with harder ledges of stratified sand, pebbles and clay protruding intermittently. The slope is still supporting a belt of trees at the base above the beach, so it is less
subject to toe erosion by tidal action than some other sites. The site faces west-northwest and the
east side receives much more sunshine than the west; by dividing the site roughly in half vertically,
testing can be carried out under both semi-shade and full sun conditions.
Site 6 is too steep and loose for planting work to be undertaken without safety ropes and harness,
and there is the additional risk of slabs of cliff falling without warning on workers below. Also,
access to the site with tools and plant materials was initially only by a tortuous trail down a nearby
gulley. Since inaccessibility to the general public is of paramount importance for successful plant
establishment, no permanent access was created, but a forty-foot timber-rung rope ladder was
constructed and slung from a support platform above the site. This provides a rapid, cheap and
removable (though strenuous) means of approaching the work area. Plant material is transmitted
to the site by a pulley system constructed alongside the rope ladder. These innovations are shown
in Figures 4 and 5.
So far, it has not been financially possible to get irrigation water onto the site, so all plantings
must rely on natural cliff moisture and rain for establishment. Experience has proved that
techniques can be developed to plant relatively efficiently under the difficult conditions of the
site. There are other difficulties that must also be overcome. To supply the hundreds of plants
required to cover the area of Site 6 alone has required many hours of manpower in terms of propagation, seed-gathering and stratification, not to mention nursery space requirements and the time
interval needed to develop nursery stock to planting size.
The range of possible plant materials, from woody trees and shrubs to herbaceous perennials
and even biennials, is considerable and the list in the accompanying table includes only the more FIGURE 4. Site 6, showing
the rope ladder down the
vertical upper cliff and the
pulley system running beside it.
*^ , * ^^.-..■^~'1 ***/
x?SVi*:,
7s-
-
■
FIGURE 5. Workers on the Cliff Project use safety
harnesses to facilitate planting on steep slopes. Here
Malcolm Clark is planting Lupinus. The slope on the
right is planted with Mentha arvensis and
Mimulus moschatus.
:.'   &t
important ones that have been either used or proposed. Availability is the ultimate controlling
factor for some species but such problems will gradually be overcome. Clearly many desirable
erosion-controlling species may not be available in commercial nurseries, so project personnel
must gather seed or cuttings and raise under cultivation the hundreds of individuals required.
The numbers in parentheses in the table show the total individuals raised for planting out so far.
Elymus mollis (Dune Wild Rye Grass) and Lupinus arboreus (Bush Lupine) have been the two
most extensively planted species. They also appear to be the most successful in terms of survival
on the site. Two native trees which propagate easily are Red Alder (Alnus rubra) and Bigleaf
Maple {Acer macrophyllum), both of which have been planted as second-year seedlings. Other
woody species that have been tried are Salix hookeriana (Hooker's Willow), Aesculus hippo-
castanum (Common Horse-chestnut), Sorbus aucuparia (European Mountain-ash), Ulex europaeus
(Common Gorse), Rubus discolor (Himalayan Blackberry), Rosa nutkana (Nootka Rose), and
Viburnum and Cotoneaster species. However, further material of these is necessary for adequate
testing.
Mentha arvensis (Field Mint) and Mimulus moschatus (Musk Monkeyflower) show promise as
rapid spreaders in semi-shade, and Verbascum thapsus (Great Mullein), a biennial plant of Interior
scree slopes, has survived planting in hot summer weather. Equisetum arvense (Common Horsetail), a natural coloniser of the lower cliff slopes, has unfortunately proved difficult to transplant
successfully. However, commercially available Coronilla varia (Crown Vetch) raised in pots has
successfully transplanted to the harder sand ledges. The Marram Grass of Europe (Ammophila
arenaria) was collected near Victoria, B.C., where it has become naturalised. It is a proven dune
stabiliser under tough conditions in Europe, but it may not be as well adapted to a cliff environment.
Some herbaceous plants have been chosen for their ability to rapidly colonise unstable areas by
seed, even though they may not have outstanding stabilising properties. Examples are Lupinus
arboreus, Cytisus scoparius (Scotch Broom), Digitalis purpurea (Common Foxglove), Verbascum
thapsus, and Epilobium angustifolium (Fireweed). Simple mixtures of agricultural cereal and
legume crops will also be tested in the future.
Spiny shrubs and trees are most important as barriers to human access in our project. Several
of these do well on sea cliffs and dunes. The Himalayan Blackberry (Rubus discolor) has the
advantage of rapid growth once it is established, and forms repellent thickets, but it is slow from %r-2
FIGURE 6. A sand talus slope at Site 6, planted with a
mixture of Ely mus mollis and Lupinus arboreus.
FIGURE 7. Lupinus
arboreus and Verbascum
thapsus on a sand slope.
FIGURE 8. Elymus mollis and Salix
hookeriana on an upper talus slope at the
foot of a vertical cliff. The Elymus in
particular does well on these sites.
FIGURE 10. Trampling and uprooting
of the plants by passersby has caused
some difficulties.
FIGURE 9. Malcolm Clark pegs out Broplene Mesh on the
talus surface at Site 6. Active erosion is evident at the top
of the photograph.
.'■ ' -'>"*)i 6
seed and needs to root from stem tips in the fall. A rapid system for propagating this desirable
plant would be of great value. The Sea Buckthorn, (Hippophae rhamnoides) forms tangled spiny
thickets on European dunes and is very tolerant of salt spray. It propagates best from root cuttings.
It is, unfortunately, hard to obtain in B.C. The Black Locust (Robinia pseudoacacia) is a fast-
growing, hardy, spiny leguminous tree which develops very deep-penetrating roots and tolerates
coastal dune conditions. It would propagate best by seed. Finally, Common Gorse (Ulex europaeus),
another nitrogen-fixing legume, is most aggressive in some sandy coastal areas. It is viciously spiny
and freely seeding. To date, we have relied on young plants and cuttings dug from bush and shore
areas of the U.B.C. campus, together with a few suitable potted species already available in the
Botanical Garden Nursery. A program of seed collection and stratification is being initiated, which
will intensify later in the season. Seeds will be stored and germinated to provide a stockpile of
material for planting next season.
An additional method of erosion control which has met with success in some situations is the
erosion mesh. This is basically a net, fixed to the soil surface, which helps retain the substrate and
slow the erosive action of wind, rain or flood water. Seed of suitable plants sown under the mesh
are able to germinate and grow through to form a close-knit mat of mesh and vegetation. Wire
Rope Industries of Vancouver have supplied us with a 25-foot square sample of Broplene Mesh
which is presently being tested on the Point Grey Cliffs.
At the present time it is not possible to predict the results of this pilot project. At least two
years will be necessary to access the effectiveness of plantings. However, our initial experiments
are promising. Public vandalism is a problem, and public awareness of the purpose of the project
must be encouraged by signs and perhaps by personal contacts on site. There is no doubt that plants
alone may not solve all the problems, but they can be effectively integrated with a sound mechanical
stabilisation program. By their natural tendency to self-perpetuate and multiply they could result
in great dollar savings on maintenance costs. Plants are also a much more publicly acceptable
method than unsightly engineering schemes. They could very simply restore the beach and cliffs
at Point Grey to a stable, natural recreational and land resource, to the satisfaction of all parties involved
PLANT MATERIAL USED IN THE CLIFF RESEARCH PROGRAM
Species: Number of Plants:
Alnus rubra (Red Alder) 39
Salix hookeriana (Hooker's Willow) 10
Sorbus aucuparia (European Mountain-ash) 4
Acer macrophyllum (Bigleaf Maple) 27
Aesculus hippocastanum
(Common Horse-chestnut) 33
Pseudotsuga menziesii (Douglas Fir) 343
Viburnum spp. 15
Cotoneaster microphyllus
(Small-leaved Cotoneaster) 15
Pernettya mucronata (Chilean Pernettya) 1
Ulex europaeus (Common Gorse) 101
Rubus discolor (Himalayan Blackberry) 6
Ribes divaricatum (Coastal Black Gooseberry)      4
Rosa nutkana (Nootka Rose) 2
Lupinus arboreus (Bush Lupine) 405
Coronilla varia (Crown Vetch) 201
Reynoutria japonica (Japanese Knotweed) 15
Mimulus moschatus (Musk Monkeyflower) 70
Verbascum thapsus (Great Mullein) 88
Mentha arvensis (Field Mint) 51
Campanula rapunculoides (Creeping Bellflower)    1
Rumex acetosella (Sheep Sorrel) 4
Bidens frondosa (Common Beggarticks) 1
Equisetum arvense (Common Horsetail) 70
Miscellaneous grasses 30
Ammophila arenaria (European Beach Grass) 23
Elymus mollis (Dune Wild Rye Grass) 818
Spartina pectinata (Prairie Cord Grass) 4
Poa douglasii ssp. macrantha
(Seashore Blue Grass) 58
Arundinaria spp. (Bamboo) 6 The Genus Dodecatheon Linnaeus in British Columbia
Member of the Family Primulaceae
DODECATHEON CONJUGENS Greene
Slim-pod Shootingstar
DODECATHEON DENTATUM W. J. Hooker
White Shootingstar
DODECATHEON FRIGIDUM Chamisso & Schlechtendal
Northern Shootingstar
DODECATHEON HENDERSONII A. Gray
Henderson's Shootingstar
DODECATHEON JEFFREYI van Houtte
Jeffrey's Shootingstar
DODECATHEON PULCHELLUM (Rafinesque) Merrill
Few-flowered Shootingstar
Natural Distribution and Habitat
The genus Dodecatheon consists of more than twelve species in North America, of which six
may be found in British Columbia in areas ranging from valleys to alpine heights. Dodecatheon
pulchellum is found in coastal prairies, Interior grasslands, saline swamps, and mountain meadows
and streams. It occurs from near sea level to above timberline, and from Alaska to Mexico and east
to Pennsylvania. Dodecatheon hendersonii is found in woods and prairies from Vancouver Island
south on the west side of the Cascades to southern Oregon, and in the Sierra Nevada of Southern
California. Dodecatheon jeffreyi occurs on wet ground, usually in meadowland or along streams,
from Alaska to northern British Columbia. Dodecatheon dentatum occurs near waterfalls and
stream banks and on shaded moist slopes on the east side of the Cascades, from southern British
Columbia to northern Oregon and central Idaho. Dodecatheon conjugens is found in seepages in
sagebrush or on montane meadows on the eastern slopes of the Cascades, from British Columbia
to northern California and east to Alberta and Wyoming.
Description of the Genus
Shootingstars are herbaceous perennials with erect scapes (in our species (2-)10-40(-60) cm tall)
and basal leaves. The plants range from glabrous to conspicuously glandular-puberulent; pubescence
may be distributed throughout or in the inflorescence only. Only D. dentatum and D. conjugens
are entirely glabrous, the other species displaying varying degrees of pubescence.
The roots are white or brownish, fleshy-fibrous, and usually produced from a short rootstock
which may be erect as in D. pulchellum or horizontal as in D. frigidum. In D. jeffreyi they are
connected by slender rhizomes and may form quite large clumps. The rootstock is absent in
D. hendersonii and D. conjugens. Small rice-like bulblets may develop among the roots at flowering
time in D. hendersonii, and sometimes in D. jeffreyi. The roots become much reduced and difficult
to see in late autumn and winter, but uptake of water leads to increased size in spring.
The leaves of Dodecatheon form a basal rosette, present at flowering time but withering by
summer. Leaves are petioled, entire to dentate, 1-6 cm wide (narrower in D. conjugens) and 2-20cm long (up to 50 cm in D. jeffreyi and D. dentatum). Size, shape and pubescence vary considerably
from one species to another, and often within species.
The flowers are perfect, regular and symmetrical, five-parted (occasionally four-parted in
D. hendersonii and commonly so in D. jeffreyi), and grouped in terminal involucrate umbels of
2 to 15(-25) flowers, or sometimes occuring singly. Pedicels are slender, recurved and 1-7 (-9) cm
long. The calyx is persistent, short-tubular, and deeply cleft into five lanceolate lobes which are
reflexed at flowering time but later erect. The corolla is showy, five-parted, short-tubular, with a
dilated thickened throat, and in our species 10-30 mm long. The lobes are long and strongly
reflexed, magenta to lavender or purple, or sometimes cream to white. The stamens are opposite
the corolla lobes, exserted, and connivent around the style. The anthers are long and slender
(lanceolate or linear-lanceolate) and often narrowing towards the apex, basally attached, dehiscent
on the inner surface, and with prominent highly coloured connectives; the filaments are short and
broad, free or united. The style is filiform, exserted and slightly longer than the stamens, the stigma
capitate and sometimes rather conspicuously enlarged. The ovary is one-celled and superior, with
many ovules on a free central placenta. Shootingstars flower from February or March to August
depending on the species and range. Dodecatheon dentatum is the only white-flowered species
found in British Columbia, the other species occasionally producing white forms but these not
common.
The fruit is a cylindric to ovoid, single-chambered capsule, in our species (5-)7-12(-20) mm long.
When ripe it splits from the tip into five acutely pointed valves, or the tip (together with the style)
forms an operculum with the walls splitting into valves below, leaving the tips of the valves
truncate. The seeds are many, small, brown, ovoid or angled, and punctate. The calyx is persistent
and erect at the base of the capsule.
Key to the Species in British Columbia
g Capsule opening by an operculum or lid at the tip, and below this by valves (teeth); connectives
(filament tissue connecting the two pollen-sacs of each anther) with cross wise wrinkles.
Anther filaments 2-4 mm long, united into a tube, purple-black; leaves ovate to obovate, with
blades only slightly longer than wide and narrowing abruptly to the petioles.. .D. hendersonii
Anther filaments less than 1.5 mm long, free or united, yellowish or dark purple to black;
leaves narrowly ovate or obovate, with blades commonly at least three times as long as wide
and narrowing gradually to the winged petioles.
Stigmas capitate (knoblike), about twice as wide as the styles at midlength; anther filaments
purple to black; petals, sepals and stamens either 4 or 5 (commonly both on the same plant)
 D. jeffreyi.
Stigmas only slightly larger than the styles; anther filaments yellowish to purple; petals, sepals
and stamens 5 D. conjugens.
Capsule opening by valves from the tip; connectives smooth, sometimes becoming longitudinally
wrinkled when dry.
Anther filaments 1.5-3.5 mm long (occasionally shorter in small flowers), yellowish to orange;
leaves narrowly ovate or spathulate, narrowing gradually to winged petioles often as long
as the blade D. pulchellum.
Anther filaments less than 1 mm long, both filaments and anthers deep red-purple to black;
leaves ovate to narrowly ovate or elliptic narrowing abruptly to the petioles.
Flowers magenta to lavender; anther filaments free or united into a shallow tube; leaves
irregularly crenate to almost entire, 0.8-3.5 cm wide and less than 15 cm long; a northern
species (Alaska, Yukon and northern B.C.) D. frigidum. 9
FIGURE 11. Dodecatheon hendersonii ssp. hendersonii. A. Habit of plant at flowering time, B. a single flower split lengthwise to
show stamens, style and ovary, C. mature capsules, D. seeds. Flowers white; anther filaments free; leaves dentate, 2-6 cm wide and up to 50 cm long;
range more southerly (southern B.C. to northern Oregon) D. dentatum.
Species Descriptions
Dodecatheon conjugens — an inland species with stout scapes and a finely purple-flecked calyx.
The flowers are usually rose-pink or magenta, sometimes white; the corolla tube is yellowish with
a red or purple wavy line at the base, the anthers and connectives yellow to purple or black. The
leaves are entire and glabrous to densely granular-puberulent. This species flowers from April to June.
Dodecatheon dentatum — a plant of stream banks and wet places. There are one or two purple dots
at the base of each corolla lobe; the tube is yellow with a red or purple wavy line at the base. The
corolla and stamens are persistent around the developing capsule. The leaves are glabrous. Flowering
is from May to July.
Dodecatheon frigidum — the corolla tube is yellow with a maroon band below. This northern alpine
species occurs at elevations up to 1700 meters. It flowers June and July.
Dodecatheon hendersonii — the scapes are often reddish, the calyx purple-flecked. The corolla lobes
are magenta to lavender (sometimes white) with a band of yellow at the base edged above with white
and below with a purple-black band. This species, with its fleshy roots and its thick leaves forming a
flattened rosette, is well adapted to summer drying. It flowers from March to June.
Dodecatheon jeffreyi — a large-leaved species common in wet places. The flowers are magenta to
lavender, sometimes pink or white. The corolla tube is cream or yellow with a reddish-purple band
below. The capsule opens usually by an irregularly shaped operculum, but occasionally by valves.
Flowering is from June to August.
Dodecatheon pulchellum — the calyx is purple-flecked, the corolla tubes magenta to lavender
-tr\ (occasionally white), the corolla tubes yellow with a red or purple wavy line at the base. This
species is widespread and variable. Flowering from April to August.
Varieties and Ornamental Cultivars
All six species are somewhat variable, but in most cases only one variant occurs in British
Columbia. AH material of D. conjugens in our area may be referred to the pubescent phase, var.
beamishiae Boivin. Dodecatheon dentatum, D. hendersonii and D. jeffreyi are all represented in
B.C. by their typical subspecies (ssp. dentatum, ssp. hendersonii and ssp. jeffreyi respectively),
though other forms of these species occur to the south.
Dodecatheon pulchellum is an extremely variable species. It has been divided at one time or
another into many different taxa, most of which are related elements in a continuous series
(Hitchcock et al., 1959). Three subspecies are recognized in British Columbia: (a) ssp. cusickii
(Greene) Calder & Taylor, a pubescent early-flowering form common on open grassy areas of the
Interior; (b) ssp. macrocarpum (A. Gray) Taylor & MacBryde, a coastal polyploid race, more or
less glabrous and commonly with large leaves; and (c) ssp. pulchellum, which resembles ssp.
cusickii but is glabrous and prefers moister, cooler habitats. Other variants of this species exist
which may or may not be worthy of taxonomic recognition. The tiny one- to two-flowered plants,
found at high elevations in the Rockies have been designated as var. watsonii (Tidestrom) C. L.
Hitchcock, but they are included here in D. pulchellum ssp. pulchellum. The Sooke form of D.
pulchellum ssp. marcrocarpum (referred to incorrectly as D. 'littorale') is a small plant with an
unusually short flowering stem. This is a desirable form for the garden, where it produces abundant
flowers and leaves but retains the short scape.
Though all of these species are excellent garden subjects, only D. pulchellum has named
cultivars. Dodecatheon pulchellum 'Album' is a white-flowered form, and D. pulchellum 'Red Wings'
has brilliant rosy flowers. All of the lavender-flowered species, however, are known to produce
white forms. Propagation
The genus can be proagated either vegetatively or by seeds. Seed should be planted as soon as
ripe in a rich, well-drained, moist soil in the shade; the plants will take from two to four years to
reach flowering size. Division of the plants is probably best done in early spring when the roots are
swollen with moisture; small pieces should root readily. New plants are continually formed
vegetatively from the thick fleshy roots or from the rice-grain bulblets found in some species.
Transplantation
The plants transplant easily, but it is preferable that large plants not be taken from areas where
they are rare. Small offsets transplant much more readily and still leave the mature plant for
others to enjoy.
Conditions for Cultivation
Dodecatheon will grow in any reasonably well-drained, moist fertile soil. The plants require
moisture during the growing season, but drier conditions when dormant, and resent crowding.
They are easy and rewarding plants to grow in the Lower Mainland area of British Columbia.
Landscape Value
All species are desirable plants for the garden. They are occasionally grown in perennial borders
but are particularly fine plants for rock gardens. Dodecatheon dentatum and D. jeffreyi adapt
readily to wet areas and stream banks and will readily seed themselves in such areas.
Availability
Dodecatheon is reasonably easily obtainable from nurseries specializing in rare and/or native
plants in this area, and also from some of the larger bulb specialists in the east.
Other Uses
The flowers of D. jeffreyi were believed by women of the Thompson Indians of British Columbia
to be useful in controlling the affections of men. They were also used as a charm to obtain wealth
and to make people give presents to the charmer. The leaves and roasted roots of D. hendersonii
were apparently eaten by some Indian tribes.
Diseases and Problems of Cultivation
The genus is relatively free of diseases and pests. Puccinia ortonia (rust) and Phyllosticta
dodecathei (leaf spot) are the most frequently reported diseases.
Origin of the Name
The generic name Dodecatheon is derived from the Greek dodeka, 'twelve', and theos or theoi,
'god'. This has been related to a name given by Pliny to a spring flower (believed to be the primrose) which was under the care of the twelve principal gods of the Greeks. Alternatively, the cluster
of crowned flowers may resemble an assembly of the Olympian gods. However, Sir W. J. Hooker
stated that Dodecatheon receives its name from the number of flowers, frequently twelve, present
in each umbel. The species name pulchellum means pretty or beautiful; hendersonii commemorates
Louis Foeniquet Henderson, an Oregon Professor of Botany; jeffreyi commemorates John Jeffrey,
a botanical collector in western North America; frigidum means growing in cold regions; dentatum,
toothed or furnished with teeth; and conjugens, joined in pairs.
The species Dodecatheon meadia was first cultivated about 1709 in England but then disappeared and was reintroduced about 30 years later. The genus was originally called Meadia by
Mark Catesby in 1752, in honour of Dr. Richard Mead, an English physician and patron of science.
Linnaeus altered the name to Dodecatheon in 1753, although meadia was retained for the first
species to be described.
11 REFERENCES
Abrams, L. 1951. Illustrated Flora of the Pacific States. Vol. III. Geraniaceae to Scrophulariaceae. Standord University Press,
Stanford.
Beamish, K. I. 1955. Studies in the genus Dodecatheon of Northwestern America. Bull. Torrey Bot. Club 82(5):357-366.
Hitchcock, C. L. et al. 1959. Vascular Plants of the Pacific Northwest. Part 4. Ericaceae through Campanulaceae. University
of Washington Press, Seattle.
Hulten, E. 1968. Flora of Alaska and Neighboring Territories. Stanford University Press, Stanford.
Ingram, J. 1963. Notes on the cultivated Primulaceae. 2. Dodecatheon. Baileya 11:69-90.
Jepson, W. L. 1957. A Manual of the Flowering Plants of California. University of California Press, Berkeley and Los Angeles.
Munz, P. A. 1959 and 1968. A California Flora and Supplement. University of California Press, Berkeley and Los Angeles.
Thompson, H. J. 1953. The biosystematics of Dodecatheon. Contr. Dudley Herb. 4:73-154.
Wyman, D. 1971. Wyman's Gardening Encyclopedia. The MacMillan Company, New York.
Standardization of Names of British Columbia Plants
12
Beginning with this issue, all scientific and common names of plants native to British Columbia
will conform to those used in the Flora British Columbia Program, a research program carried out
for the past three years at the Botanical Garden. The results of this research will be published in
book form during 1976 by the University of British Columbia Press. The publication will appear
as part of the Technical Bulletin Series of the Botanical Garden, under the title "Vascular Plants
of British Columiba — A Descriptive Resource Inventory". The Flora British Columbia Program
will be the subject of a forthcoming article in Volume 7 Number 1 (the Spring 1976 issue) of
Davidsonia.
Climatological Summary^
Data
January
February
March
Mean temperature
2.8°C
2.4°C
4.9°C
Highest temperature
10.6°C
8.3 °C
10.0°C
Lowest temperature
-5.6°C
-6.1°C
-1.7°C
Grass minimum temperature
-10.6°C
-12.8°C
-8.9°C
Total rainfall/No. days with rainfall
139mm/18
119mm/20
104mm/18
Total snowfall/No. days with snowfall
208mm/9
343mm/12
0/0
Total hours bright sunshine/possible
57.1/265.4
64.4/278.4
165.0/361.2
Max. wind speed in km for 1 hour/direction
26/NW
24/NW
26/SE
Mean kilometers of wind at 1 m
125.8
114.9
142.4
Mean kilometers of wind at 13 m
184.1
164.0
202.6
'Site: The University of British Columbia, Vancouver, B.C., Canada
Position: lat. 49° 15'29"N; long. 123° 14'58"W. Elevation: 104.4m BOTANICAL GARDEN STAFF
'l'
Fertile shoots of the Giant
Horsetail, Equisetum
telmateia var. braunii.
Director
Dr. Roy L. Taylor
Supervisor of Operations
Mr. Kenneth Wilson
Research Scientist (Cytogenetics)
Dr. Christopher J. Marchant
Research Scientist (Horticulture)
Dr. John W. Neill
Research Assistants
Miss Andrea M. Adamovich
Mrs. Sylvia Taylor
Secretary to the Office
Mrs. Susan Weiner
Plant Accession System
Mrs. Annie Y. M. Cheng
Education Coordinator
Mr. David Tarrant
Horticulturists
Mr. A. James MacPhail (Alpine Garden)
Mr. Gordon J. Ramsdale (Nursery)
Gardeners
Mr. William R. Johnston
(Area Manager, Upper Campus)
Mr. Pierre Rykuiter
(Area Manager, Upper Campus)
Mr. Harold Duffill
Mr. Leonard Gibbs
Mr. Robert Kantymir
Mr. Murray J. Kereluk
Mr. Paul Kupec
Mrs. Bodil Leamy
Mrs. Elaine V. Lemarquand
Mr. Sam Oyama
Mr. Ronald S. Rollo
Mr. Allan A. Rose
Mr. Douglas G. Smythe
Mr. Isao Watanabe
Mr. Thomas R. Wheeler
Flora British Columbia Program
Dr. Roy L. Taylor (Editor)
Dr. Bruce MacBryde (Associate Editor)
Mrs. Olga H. MacBryde (Research Assistant)
Miss Linda R. Martin (Research Assistant)
Mrs. Rosamund A. Pojar (Research Assistant) The yellow spathes of Lyskhiton
americanum (American Skunk-
Cabbage or Swamp Lantern) appear
in the early spring and form patches
of vivid color in wet places.
DAVIDSONIA
Volume 6       Number 1       Spring 1975
Contents
Cliff Erosion Control with Plants     1
The Genus Dodecatheon in British Columbia     7
Standardization of Names of British Columbia Plants    12
Climatology    12
l»L,r„,
D-D BY PH1CE PRINTING LTD.

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