ISSN 1188-603X

No. 381 September 12, 2007 Victoria, B.C.
Dr. A. Ceska, P.O.Box 8546, Victoria, B.C. Canada V8W 3S2

BOTANY BC, 2007 OSOYOOS MAY 10 to MAY 13, 2007

From Chris Pielou and Sharon Niscak, Comox

This year's Botany BC was held in Osoyoos, from 10-13 May. Headquarters was the Spirit Ridge Resort and the adjacent Nk'Mip Desert Cultural Centre. Elizabeth Easton masterminded all the planning with her customary skill, she and Terry McIntosh were our hosts.

The weather was warm and the sun shone on our two field-trip days, when we split into two groups, each spending a day on each trip.

Trip 1. The first part of Trip 1 was led by Mike Miller, and took us up open hillsides overlooking the Similkameen River near Chopaka in the morning. The second part of Trip 1, led by Adolf and Oluna Ceska, took us along the road up Mt Kobau almost to the summit, where germinating Floerkea proserpinacoides and some last year's stalks of Agastache urticifolia were found. When we reached the snow close to the top on Mt. Kobau, Jim Ginns and Oluna Ceska showed us some very interesting snow bank fungi (cf. BEN # 377 April 12, 2007), including Caloscypha fulgens, Cheilymenia fimicola (on old cow dung), Cheilymenia raripila (on cow dung), Clitocybe albirrhiza, Clitocybe glacialis, Discina perlata, Erythricium laetum (comon snow bank mushroom in WA, not previously collected in British Columbia), and Peziza sp.

Trip 2, led by Terry McIntosh, went to exceedingly dry benchlands (cactus and tumbleweed country) east of Highway 27 between Osoyoos and Oliver in the morning; and in the afternoon, to the foot of McIntyre Bluff (overlooking Vaseux Lake) and on to White Lake Grasslands and Haynes Lease. The botanizing was splendid. The low-altitude bench lands of the Okanagan Valley are typically covered with sage-brush (Artemisia tridentata), rabbit-brush (Ericameria nauseosa), and bluebunch-wheatgrass (Psudoroegneria spicata), plus a multitude of attractive flowering herbs. Those in flower included Erigeron linearis, Lithospermum incisum, Hydrophyllum capitatum, Triteleia grandiflora, Calochortus macrocarpus, Lewisia rediviva and Balsamorrhiza sagittata. Mike was also able to show us red- listed Linanthus septentrionalis and blue-listed Halimolobus whitedii.

The very southern end of the valley, including Osoyoos, has abundant antelope-brush (Purshia tridentata) as well as sage- brush which, because it is so much darker, makes for a marked change in the scenery. And with the antelope-brush we saw some of the plants whose range in Canada is restricted to the extreme southern end of the Okanagan valley, such as Artemisia tripartita, Halimolobus whitedii, Erigeron poliospermus and Leptodactylon pungens. These are some of the plants species that give the region its exceptional biodiversity. Other rarities seen by some of our group were two blue-listed snakes: western rattlesnake (Crotalus oreganus) and racer (Coluber costrictor). They all need the protection that only the planned South Okanagan-Similkameen National Park can provide and that is still not a fait accompli. We must write more letters to the Prime Minister and Minister of the Environment (from the informed to the ignorant) to reinforce the letters we sent last year.

Besides the field trips we had two interesting and convivial evenings at the magnificent Nk'Mp Desert Cultural Centre. We were welcomed on our first evening by Modesta Stelkia Betterton and Chief Clarence Louie and watched the fascinating film "Coyote Spirit." During the evening we were also treated to the exquisite details of nature with its wondrous geometry via a slide show set to music. Orville Dyer's photography captured the form, light and beauty that surrounds us when we open our eyes and examine the intricacies of our earth. Ted Lea illustrated the use of historical mapping in determining eco-system modification and shifting dynamics by comparing historical photographs, with identifiable landmarks, to present day photographs. Knowledge of the historical context of the earlier photographs is relevant because early settlement was accompanied by practices that changed the environment significantly from pre-contact land use.

On our final evening, following a feast of salmon cooked traditionally over a bonfire, the Osoyoos Indian Band Youth Dancers engaged the audience with traditional dancing. Participation by the very young children guided by older teenagers illustrated how cultural inclusiveness is valued in traditional learning. The youngest Botany BC members joined the dancers with energy and joy. Terry Millar presented an entertaining overview of activities in the South Okanagan. For the first time Botany BC honoured the substantial contribution of Oluna and Adolf Ceska to the study of botany. All of us have benefited from the years of dedication, research and botanical support of these remarkable botanists. An entertaining slide show compiled by the Botany BC committee highlighted their achievements. Oluna and Adolf were invited to choose the next location for Botany BC, but they preferred to leave the decision to the whole group.

That was Botany BC in 2007-memorable for the beautiful landscapes, flora and fauna. Thank you Elizabeth, Terry, Adolf, Oluna and Mike for organizing this great trip. For Botany 2008, we'll meet at Powell River and plan to visit Savary and Texada Islands.

[It was a pity that for quite a few of us our nice memories of BOTANY BC 2007 were marred by a fierce attack of Norwalk virus (Norovirus) that troubled about 40 per cent of participants. Let's hope that all of those afflicted will remember the nice botanical moments rather than the negative side of the trip. - AC]


Weber, W. A., & R. C. Wittmann. July, 2007.
Bryophytes of Colorado. Mosses, Liverworts, and Hornworts. Pilgrims Process, Inc., Santa Fe, New Mexico. 238 p. + 8 Plates. US $29.95. Printed in U.S. and Europe and available from Amazon, Barnes & Noble, and any book store.

This is the first comprehensive work on Colorado bryophytes, 401 mosses and 106 liverworts and hornworts, compared to 292 (mosses only) reported in Weber (1973) Guide to the Mosses of Colorado. This is the result of a decade of concentrated field and herbarium work, not to mention over 75 years preparatory studies by the senior author and 20 by the junior.

Colorado has been a blind spot in the map of North American bryophytes, and while it has no known endemic species, there are a significant number that are disjunct from the Holarctic region, Middle Asia including western China, the Russian Altai, Turkestan, and Central and South America.

The book comprises an introduction outlining the history of bryological collecting, explanation of the scientific names, notes on the people who described the species, keys to the genera and species, citations of significant specimens, a glossary, index by specific epithets, bibliography, and an alphabetical catalog with lists of synonyms that have been applied in earlier papers.

Since this is a fairly technical book, we now are beginning to refine our electronic Moss Primer to help beginners to become acquainted with the easily recognizable common species of Colorado.


From: Paul M. Catling, Biodiversity, National Program on Environmental Health, Agriculture and Agri-food Canada, Wm. Saunders Bldg., Central Experimental Farm, Ottawa, Ontario, Canada K1A 0C6 [ ]

Euphorbia esula is a major weed of both agriculture and natural landscapes in Canada (Biesboer and Eckardt 1987, Haber 1997). Especially in the prairie provinces it interferes with agricultural production costing millions in reduced carrying capacity of rangeland, and it also displaces many native species and changes natural habitats. Recently we have received many questions regarding its identification and relationship to other species found in Eurasia and possibly occurring in North America.

Development of a database of specimens in Canadian herbaria at DAO required checking of specimen identifications and the following notes were prepared as part of this process. These notes, reproduced below, will satisfy many of the requests for information that we have received, especially regarding identification. Comments and new information are welcome.

A brief overview

Leafy Spurge is native to Eurasia where it was once divided into numerous species by taxonomists in different countries. In fact more than 60 species have been described in the aggregate. Recent studies have suggested several related species in the group and the recent Canadian study of Crompton et al. (1990) suggested that four taxa occur in North America E. agraria Bieb., E. cyparrisias L., E. esula L., and the hybrid E. X pseudoesula Schur. The group of E. esula and its close relatives (within section Esula Dumort.) is distinguished by smooth seeds, raylet leaves not joined at the base, capsules 4-5 mm wide, and leaves pinnately veined (Smith & Tutin 1968). The group is probably best conceived as about 7 species (E. agraria, cyparissias, esula, lucida, nevadensis, salicifolia, and undulata). There are also 3 hybrids and E. boissieriana, the relationships of which are unclear.

The last extensive taxonomic study of the group was that of Crompton et al. published in 1990. It contributed some important observations, but much more detailed taxomomic work is needed in this difficult group. Although useful, recent studies have been localized (e.g. Geltman 1996) or general (e.g. Rowe 1997). It is remarkable that the last time substantial taxonomic work was done on this complex, was 17 years ago, yet the need is clear and it is one of the world's worst weeds.

Much information has been published on biology, control and impact, both in the scientific and popular literature and on the web (e.g. Best et al. 1980, Haber 1997). Its expansion in Canada occurred mostly after 1933 (see maps in Haber 1997). It continues to invade, at least on a local scale, and has a number of effective seed dispersal mechanisms. Seeds lodge in mud on vehicles and are dispersed by a variety of animals (e.g. Blockstein et al. 1987; Pemberton 1988; Wald et al. 2005). Root- feeding Flea Beetles, including 5 species of Apthona, most of which are established across Canada, have proven effective in biological control reducing some infestations by 90%. Since the cost of spraying herbicide to achieve control is excessive, these beetles may already have saved many millions. Another control agent, the Spurge Hawk Moth (Hyles euphorbiae) has proven to be a useful control agent as a larvae (e.g., Forward,and McCarty. 1980) but may also be beneficial as an adult in pollinating an endangered native orchid (Jordan et al. 2006). It may also be of interest that milky juice of leafy spurge causes a severe dermatitis in some people and the plants are poisonous to most livestock.

Annotated list of species occurring in Eurasia, Canada, and the United States (species not reported from Canada are in square brackets, the list includes partial synonymy largely from Smith & Tutin (1968) and Govaerts et al. (2000). A complete list of synonyms and their places of publication may be found in the latter reference.

Euphobia agraria Bieb., URBAN SPURGE, (E. podperae Croizat)

Widesrpead in southeastern Europe, introduced in North America. In Canada known only from Alberta, where collected at Edgerton and Lonely Lake on the Bow River, Alberta (Crompton et al. 1990). It is also known from the midwestern and notheastern U.S (Kartesz & Meachum 1999). A few varieties requiring more study have been described on the basis of leaf shape (Smith & Tutin 1968).

[Euphorbia boissieriana (Woronow) Prokh.]

Although sometimes considered a synonym of E. esula (e.g. Davis 1982), this taxon was recognized as a species by Govaerts et al. (2000) and Stace et al. (2005). This latter species (and its putative hybrid with E. esula) are separated from subsp. tommasiniana by their slightly wider and more acuminate leaves (Stace et al.2005).

Euphorbia cyparissias L., CYPRESS SPURGE (Galarhoeus cyparrisias (L.) Small ex Rydb., Tithymalus esula (L.) Hill)

There are both diploid and tetraploid races in North America and Europe, but in Ontario some of the diploid plants lack viable pollen (Moore & Frankton 1969).

Euphorbia esula L. sensu lato

Having examined hundreds of specimens from across Canada, it is concluded that infrataxa should not be recognized as suggested by some recent authors (Crompton et al. 1999, Evans et al. 1991). A single plant may often possess characters of both subspecies (see below). For example an individual plant may have both linear acute and oblanceolate obtuse leaves. Furthermore leaf shape and width appears to vary continuously among individuals and has a normal distribution. The number of rays is at least to some extent related to plant size. Two subspecies have been segregated using the following characters. Notes on these follow the key.

1a. Umbel with 5-9 rays; axillary rays 2-12; leaves linear to 
    lanceolate and acute or subacute 	E. esula subsp. 
    tommasiniana and E. X pseudovirgata and 
    E. X gayeri]
1b. Umbel with 8-17 rays; axillary rays 8-20; leaves oblanceolate 
    to broadly ovate or obovate and obtuse or emarginate 
    E. esula var. esula

(1) subsp. esula, LEAFY SPURGE, WOLF'S-MILK (E. borodinii Sambuk, E. filicina Portenschl, E. imperfoliata Vis., E. intercedens Podp., E. pancicii G. Beck, E. pseudoagraria Smirnov, E. pseudovirgata (Schur) Soo, Galarhoeus esula (L.) Rydb., Tithymalus esula (L.) Hill

Plants of E. esula with lanceolate instead of oblanceolate leaves have sometimes been segregated as E. waldsteinii (e.g. Stace et al. 2005).

(2) subsp. tommasiniana (Bertol.) Kuzmanov, LEAFY SPURGE, WOLF'S-MILK (Euphorbia esula L. var. uralensis (Fisch. ex Link) Dorn, E. subcordata Ledeb., E. tenuifolia Lam., E. uralensis Fisch. ex Link, E. virgata Waldst. & Kit., non Desf., E. waldsteinii (Soják) Radcl.-Sm., Tithymalus uralensis (Fisch. ex Link) Prokhanov)

Although it is identified by its narrow leaves, this character may not have been part of the original concept (Crompton et al. 1990) so that some additional work is required, not only to establish rank, but also to verify the application of the name.

This taxon was reported for Canada by Stahevitch et al. (1988) but not in a later publication involving the same author (Crompton et al. 1990) which accounted for all Canadian species. Thus it is presently considered not to occur in Canada, but there are periodic references to its occurrence in Saskatchewan based on the report of Stahevitch et al. (e.g. Kartesz & Meachum 1999). In the U.S. it is reported from several states in the upper midwest and in the Great Lakes region (Kartesz & Meachum 1999).

Some European workers have recently recognized this taxon at the rank of species (E. virgata Waldst. & Kit, e.g. Geltman 1998). It has most recently been recognized at the rank of subspecies (subsp. tommasiniana (Bertol.) Kuzmanov, e.g. Govaerts et al. 2000). In North America it has been treated at the rank of variety (Euphorbia esula L. var. uralensis (Fisch. ex Link) Dorn, Vascular Plants of Wyoming p. 296. 1988, Kartesz & Meachum 1999), Recognition appears unwarranted (see above) but if recognized, varietal rank seems most appropriate and it is desirable to maintain the name currently used in North America. However, it is treated as a subspecies in the recent world list of Euphorbia species (Govaerts et al. 2000).

Euphorbia esula L. var. orientalis Boiss. was reported from Connecticut by Croizat (1945) under the name"E. virgata orientalis." Croizat (1945) thought that it belonged within E. iberica and described it as a taller and stouter plant than E. virgata. The latter has most recently been treated as a synonym of E. esula var. uralensis (e.g. Smith & Tutin 1968) and var. orientalis has has been treated as a synonym of E. virgata (Davis 1982). Both are currently treated as synonyms of subsp. tommasiniana (Govaerts et al. 2000).

Euphorbia waldsteinii (Soják) Radcl.-Sm., recognized as the lanceolate-leaved member of the "esula aggregate" by Stace et al. (2005), is treated as a synonym of subsp. tommassiniana by Govaerts et al. (2000).

Euphorbia X gayeri Borbás & Soó, a hybrid of E. cyparissias and E. esula subsp. tommasiniana has been reported from from central Europe to Romania. It would be difficult to distinguish since subsp. tommasiniana closely resembles E. cyparissias.

Euphorbia X pseudovirgata (Shur.) Soo, a putative hybrid of subsp. esula and ssp. tommasiniana, is treated as a synonym of E. esula var. esula by some recent authors but retained by Govaerts et al. (2000). It is reported from Europe from the region of Poland to Bulgaria. Since the subspecies intergrade, the recognition of this hybrid seems unwarranted.

[E. lucida Waldst. & Kit.] SHINING SPURGE, (Galarhoeus lucidus (L.) Rydb., Tithymalus lucidus (L.) Klotzsch and Garcke]

Although E. lucida was reported for Canada (at Edgerton, Alberta by Croizat in 1945), the report was rejected by Crompton et al. (1990) since the specimen was misidentified as E. agraria. Boivin (1966, 1967) identified E. lucida on the basis or cordate leaves (although he changed his key later (Boivin & Cruise 1978). Plants with cordate leaves are now placed with E. agraria (e.g. Smith & Tutin 1968) so Boivin's reports (and others based on his) for both Alberta and Saskatchewan are discounted. Boivin and Cruise (1978 ms) suggested that the reports E. lucida for Ontario were based on a specimen at TRT correctly assigned to E. esula. These earlier erroneous reports may be the basis for more recent listings for the province. This species has also been reported from three states in the northeastern U.S. (Kartesz & Meachum 1999). It is native to central and southeastern Europe (Smith and Tutin 1968).

[E. nevadensis Boiss. & Reuter]

A species closely related to E, agraria but smaller (leaves less than 30 mm long instead to 80 mm). It occurs in southern and eastern Spain.

E. X pseudoesula Schur, HYBRID CYPARISSIAS AND ESULA (?E. X figertii Dorfler)

This hybrid of E. esula var. esula and E. cyparissias, well known in Europe. It was first reported from North America by Moore and Frankton (1969) from the counties of Huron, Bruce and Muskoka in Ontario. It is most easily recognized as a plant that appears to be E. esula but has unusually numerous and crowded, and small leaves (cauline leaves less than 4 cm long and less than 5 mm wide). Moore and Frankton (1969) found only hybrids between diploid E. esula and tetraploid E. cyparissias, the hybrid having a chromosome number of 2n=50. Since two expressions of the hybrid occur in Europe, one possibly involving a diploid race of E. cyparissias with viable pollen, and since the Canadian hybrids form a small amount of seed (Moore & Frankton 1969) possibly allowing backcrossing, there may yet be more variation in this hybrid in Canada than has currently been noted.

[E. salicifolia Host], WILLOW-LEAVED SPURGE]

Known in Europe from Austria to Turkey.

[E. undulata Bieb.], UNDULATE-LEAVED SPURGE]

A native of S.E. Russia and W. Kazakhstan

Key to the species of the Euphobia esula group occurring in Canada, United States and Eurasia (Species not reported from Canada are in square brackets). Additional taxonomic research is needed to improve this key.

1a. Leaf cordate (lobed) at the base 	2
1b. Leaf base not cordate 	3

2a. Leaves to 30 mm long 	[E. nevadensis]
2b. Leaves to 80 mm long 	E. agraria

3a. Plants pubescent and with ovate or ovate-lanceolate leaves	
    [E. salicifolia] 
3b. Plants glabrous or if pubescent with linear to
    linear-lanceolate leaves;	4

4a. Leaves emarginate, oblanceolate or elliptic-obovate, with
    undulate margins; plants rhizomatous 	[E. undulata]
4b. Lacking the combination of characters in 4a, 
    leaves emarginate or not, oblanceolate or not, lacking 
    undulate margins; plants rhizomatous or not 	5

5a. Leaves shiny 	[E. lucida]
5b. Leaves dull 	6

5a. Leaves lanceolate and acuminate 	[E. boisseriana]
5b. Leaves linerar, lanceolate, oblanceolate, broadly ovate,
    obovate, and acute or emarginate 	

6a. Leaves lanceolate to broadly ovate, mostly more than 4 mm 
    wide; lateral branches with few with scattered leaves 	
	E. esula sensu lato (for notes on subspecies see above) 
6b. Leaves linear, less than 4 mm wide; many lateral branches
    with crowded leaves 	7

7a. Cauline leaves less than 2.6 (3) mm wide; floral leaves 
    4-6 mm long		E. cyparissias and [E. X gayeri]
7b. Cauline leaves more than 2.6 mm wide; floral leaves 
    10-13 mm long		E.  X pseudoesula
Best, K.F., G.G. Bowes, A.G. Thomas and M.G. Maw. 1980.
The biology of Canadian weeds 39. Euphorbia esula L. Can. J. Plant Sci. 60: 651-663.
Biesboer, G.G. and N. Eckardt. 1987.
Element Stewardship Abstract for leafy spurge (Euphorbia esula). The Nature Conservancy, Minneapolis. 17 p.
Blockstein, D.E., B.D. Maxwell and P.K. Fay. 1987.
Dispersal of leafy spurge seeds (Euphorbia esula) by Mourning Doves (Zenaida macroura). Weed Technology 1(4): 314-318.
Boivin, B. 1967.
Flora of the prairie provinces, part 1. Phytologia 15(6): 121-159.
Boivin, B. 1966.
Énumération des plantes du Canada, II - Lignidées. Naturaliste Can. 93: 371-437.
Boivin, B. and J.E. Cruise. 1978.
The spurges of Canada. Agriculture Canada, manuscript. 223 p.
Croizat, L. 1945.
"Euphorbia esula" in North America. American Midland Naturalist 33: 231-243.
Crompton, C.W., A.E. Stahevitch and W.A. Wojtas. 1990.
Morphometric studies of the Euphorbia esula group (Euphorbiaceae) in North America. Can. J. Bot. 68: 1978-1988.
Davis, P.H., J.R. Edmondson, R.R. Mill and K. Tan. 1982.
Flora of Turkey and the east Aegean Islands, vol. 7. Edinburgh University Press. 947 p.
Forward, J.R and M.K. Mc Carty. 1980.
The control of Leafy Spurge, Euphorbia esula, in Nebraska, USA, with the Spurge Hawk Moth, Hyles euphorbiae. Weed Science 28(3): 235-240.
Geltman, D.V. 1998.
Taxonomic notes on Euphorbia esula (Euphorbiaceae) with special reference to its occurrence in the east part of the Baltic region. Ann. Bot. Fennici 35: 113-117.
Govaerts, R., D.G. Frodin, and A. Radcliffe-Smith. 2000.
World Checklist and Bibliography of Euphorbiaceae (and Pandaceae). Part 2. Kew: Royal Botanic Gardens, Kew. Pp. 417-921.
Haber, E. 1997.
Invasive exotic plants of Canada Fact Sheet No. 9. Environment Canada 19 p. See also Leafy Spurge, Euphobia esula at
Jordan, C.A., G.M. Fauske, M.O. Harris, and D. Lenz. 2006.
First record of the spurge hawkmoth as a pollen vector for the western prairie fringed orchid. Prairie Naturalist 38(1): 148-159.
Kartesz, J.T. and C.A. Meachum. 1999.
Synthesis of the North American flora. Version 1.0. Biota of North America Program, University of North Carolina, Chapel Hill.
Moore, R.J. and C. Frankton. 1969.
Euphorbia X pseudo-esula (E. cyparissias X E. esula) in Canada. Canadian Field Naturalist 83(3): 243-246.
Pemberton, R.W. 1988.
Myrmecochory in the introduced range weed, Leafy Spurge, Euphorbia esula. American Midland Naturalist 119(2): 431-435.
Rowe, M.L., D.J. Lee, S.J. Nissen, B.M. Bowditch and R.A. Masters. 1997.
Genetic variation in North American leafy spurge (Euphorbia esula) determined by DNA markers. Weed Science 45(3): 446-454.
Smith, A.R. and T.G. Tutin. 1968.
7. Euphorbia L. Pp. 213-226 in T.G. Tutin et al., Flora Europaea, volume 2, Rosaceae to Umbelliferae. Cambridge University Press.
Stace, C., R. Vander Meijden (ed.) and I. de Kort (ed.). 2005.
Interactive flora of NW Europe. A World Biodiversity Database Project based on a DVD-ROM accessed at (based on Stace, C.A., 1997. New Flora of the British Isles. 2nd Edition. Cambridge University Press. XXVII + 1130 p.)
Stahevitch, A.E., C.W. Crompton, and W.A. Wojtas. 1988.
Cytogenetic studies of leafy spurge, Euphorbia esula, and its allies (Euphorbiaceae). Can. J. Bot. 66: 2247-2257.
Stahevitch, A.E., C.W. Crompton and W.A. Wojtas. 1988.
Biology of Canadian weeds. Euphorbia cyparrisias L. Can J. Plant Science 68: 175-191.
Wald, E.J., Kronberg, S.L., Larson, G.E. and Carter-Johnson, W. 2005.
Dispersal of Leafy Spurge (Euphorbia esula L.) seeds in feces of wildlife. American Midland Naturalist 154(2): 342-357.

Send submissions to
BEN is archived at