Flora of the Canadian Arctic Archipelago

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S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Draba crassifolia Graham

English: Snowbed whitlowgrass,

French: Drave à feuilles charneues.

Brassicaceae (Cruciferae), Draba family.

Published in Edinburgh New Philos. J. 7:182. 1829.

Synonymy. Draba parryi Rydberg, Bull. Torrey Bot. Club 29: 241. 1902.

Draba crassifolia var. parryi (Rydberg) O.E. Schulz, Pflanzenreich (Engler) [Heft 89] 4, Fam. 105: 327. 1927.

Vegetative morphology. Plants 1–6 cm high; perennial herbs; caespitose, or not caespitose. Taproot present. Ground level or underground stems horizontal, or vertical, or absent; elongate, or compact. Caudex present (weak). Aerial stems erect. Leaves mainly basal, or basal in a rosette; alternate; dying annually and non-persistent. Petioles absent. Leaf blades simple. Leaf blade bases attenuate and truncate. Blades (4–)5–11(–15) mm long, 1–2 mm wide, oblong or spatulate, veins reticulate or appearing single-veined or with inconspicuous veins. Blade adaxial surface glabrous. Blade abaxial surface glabrous. Blade margins entire, glabrous or with non-glandular hairs (a few long cilia on some, but not all, basal leaves); apices acute.

Reproductive morphology. Flowering stems two or more per plant; without leaves. Inflorescences head-like and racemose; dense (in flower), or diffuse (in fruit); elongating as the fruit matures. Pedicels glabrous. Flowers per inflorescence 3–10(–12); small (small for a Draba); radially symmetrical (actinomorphic). Sepals conventional; 4; free; 0.6–1 mm long; 1.3–1.9 mm wide; green (sometimes with hyaline margins). Calyx without sessile glands; glabrous. Petals conventional; free; 4; yellow (when flowers first open), or white (as flowers fade); without contrasting markings; spatulate, or obtriangular; unlobed (or very slightly lobed); 1.8–2.5 mm long; 0.7–1 mm wide. Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous. Anthers yellow; ovoid (tiny); 0.2–0.3 mm long. Ovary superior; carpels 2; syncarpous. Ovaries ovate; glabrous. Styles 1; 0.1–0.3 mm long; straight. Stigmas per ovary 1(–2). Placentation parietal. Ovules per ovary (16–)20–24(–28). Fruit stalked; stalk 2–5 mm long; dry; a silique; obovate; green at maturity; 4–5 mm long; 1.2–1.4 mm wide; glabrous; distinctly flattened; dehiscent; shedding the outer walls to expose a thin inner wall, with the seeds attached at the margins on either side. Styles persisting in fruit 0.05–0.1(–0.2) mm long. Seeds (16–)20–24(–28); 0.4–0.6 mm long; brown; surfaces smooth.

Chromosome information. 2n = 40 and 80.

2n (4x or 8x, x = 10 or 5) = 40. Heilborn (1941, Greenland); Mulligan (1966, 1975, North America); Engelskjøn and Knaben (1971, northern Norway); Dalgaard (1989, western Greenland); Brochmann et al. (1993, Norway); Mulligan (2003);

2n(8x or 16x) = 80. Mulligan (1966, North America).

Ploidy levels recorded 4x, 8x, 16x,.

Ecology and habitat. Substrates: snow patches (herbmats and on snowbeds); imperfectly drained moist areas, seepage slopes; moss; with high organic content; acidic.

North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Rare. Arctic, alpine. Arctic islands: Baffin, Southampton.

Northern hemisphere distribution. Amphi-Atlantic, or North American. Northern Fennoscandian, West Alaska (?), North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, West Greenland, East Greenland.

Illustrations. • Habitat. Tiny plants less than 5 cm high with yellow flowers borne on leafless flowering stems. Nunavut, Baffin Island, Apex. Aiken and Iles 02–067. CAN. Scale bar in cm. • Close-up of plant. Plants with yellow flowers borne on leafless flowering stems. Note the shiny dark green glabrous leaves. Flowers are yellow in bud but fade to white with age. Nunavut, Baffin Island, Apex. Aiken and Iles 02–067. CAN. Scale bar in cm. • Close-up of flowers. Flowers with yellow unlobed petals in bud that fade to white on opening. Sepals are green, glabrous and have a hyaline margin. Nunavut, Baffin Island, Apex. Aiken and Iles 02–067. CAN. • Arctic Island Distribution.


This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.

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