Flora of the Canadian Arctic Archipelago
Brassicaceae (Cruciferae), Draba family.
Published in Type: Canada: Nunavut, Bylot Island, Baffin Land. Holotype: K.
Synonymy. Draba adamsii Ledeb., Fl. Ross. 1: 177. 1842.
Draba micropetala auct., non Hooker 1825.
Draba oblongata auct., non R. Br. ex DC., 1821.
Vegetative morphology. Plants (1.5–)4–8(–10) cm high; perennial herbs; caespitose. Taproot present. Ground level or underground stems vertical. Caudex present (branching). Aerial stems erect. Aerial stem trichomes spreading. Leaves mainly basal, or basal in a rosette; alternate, or whorled; marcescent (with a moderate build-up of dead leaves). Petioles absent. Leaf blades simple. Leaf blade bases truncate and attenuate. Leaves not grass-like. Blades (8–)10–16(–20) mm long, 2–4 mm wide, obovate or spatulate, appearing single-veined (vein prominent at the base of the leaf) or with inconspicuous veins (towards the apex). Blade adaxial surface glabrous (in the centre) or hairy (towards the margins), hairs simple or branched (irregularly), hairs sparse or moderately dense, hairs white, or translucent. Blade abaxial surface hairy, hairs sparse or moderately dense (the long stellate branches overlapping may make the hairs appear dense), hairs white, hairs curved or stellate, hairs spreading. Blade margins entire, with non-glandular hairs; apices acute.
Reproductive morphology. Flowering stems without leaves. Flowering stem hairs branched (irregularly forked), or stellate; shorter than the diameter of the flowering stem; white or translucent. Inflorescences head-like; dense; globose or sub-globose; 0.5–0.8 cm long; 5–8 mm wide (rarely to 25 mm long in fruit); not elongating as the fruit matures (usually). Pedicels with non-glandular hairs. Flowers per inflorescence (2–)3–5(–7); small (small for draba); radially symmetrical (actinomorphic). Sepals conventional; 4; free; 0.9–1.2 mm long; 1.7–2.3 mm wide; green and purple. Calyx hairy (with long simple hairs). Calyx hairs non-glandular; white or translucent. Petals conventional; free; 4; yellow (CAN 451325), or white (creamy, CAN 431936); obtriangular; unlobed, or slightly lobed or undulating; 2.5–3 mm long; 0.7–1 mm wide (at the top, 0.2 mm at the base). Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous. Anthers yellow; sub-globose; 0.3–0.4 mm long. Ovary superior; carpels 2; syncarpous. Ovaries ovate; hairy. Ovary hairs sparse; white; spreading; straight. Styles 1; 0.05–0.1 mm long; straight. Stigmas per ovary 1. Placentation parietal. Ovules per ovary 12–20. Fruit stalked; stalk (1–)2–6 mm long; dry; a silique; ovoid; brown (with drab olive tones); 7–8.5 mm long; 3.5–4.5 mm wide; hairy (with sparse, short, simple hairs); surface venation reticulate; 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 mm long (a tiny stump). Seeds 12–20; 1.2–1.4 mm long; brown; surfaces smooth.
Chromosome information. 2n = 32.
2n = 32. Packer and McPherson (1974, northern Alaska, Barrow, as 'adamsii'); Zhukova et al. (1973, northeastern Asia, as 'micropetala'); Zhukova and Petrovsky (1984, northeastern Asia, as 'pauciflora'; 1987b, northeastern Asia, as 'oblongata'); Brochmann et al. (1993, Svalbard, as 'micropetala'); Mulligan (2003).
Ploidy levels recorded 4x.
North American distribution. Alaska, Yukon (?), Northwest Territories Islands, Nunavut Islands. Arctic islands: Devon, Ellesmere, Axel Heiberg, Parry islands (Melville), Banks, Somerset (Additional records from Elven , 2005).
Northern hemisphere distribution. Circumpolar. Svalbard Franz Joseph Land, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, YanaKolyma, West Chukotka, Wrangel Island, East Chukotka, North Alaska Yukon, Central Canada, Labrador Hudson Bay (?), Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. Rollins (1993) gave p. 147 for Ledebour's publication of D. adamsii.
Elven et al. (2003) noted that chromosome counts of 2n = 32, listed by Löve and Löve (1975), under D. adamsii Ledeb., Zhukova et al. (1973, from Siberia), and Mulligan (1974a, from Canada?), may also belong here, but this needs to be confirmed by examining the identity of the vouchers.
Illustrations. • Close-up of plant. Note the narrow petals 2.5–3 mm long that are a 'dirty' pale yellowish colour and the long coarse simple hairs on the leaf margins (a distinction from D. micropetala). July, 1987. Norway, Svalbard, Longyearbyen. No voucher. Photograph by R. Elven. • Close-up of young inflorescence. Tiny plant 1.5 cm tall, covered in dense stellate to irregularly branching hairs giving it a greyish appearance. Flowers with purplish, hairy sepals and yellow petals. Gathered from low polygons of drained Drepanocladus peat. Nunavut, Victoria Island, Namaycush Lake. CAN 527906. • Close-up of base of plant. Basal cushion pulled apart in pressing shows a limited build-up of marcescent leaves, flowering stems without leaves, and subcapitate fruiting inflorescences (infructescences) with 4–5 ovoid siliques. Nunavut, Ellesmere Island, growing on a damp rocky slope. J.H. Soper 8311. 4 August, 1958. CAN 183638. • Fruiting inflorescence. Immature infructescence (fruiting inflorescence). Note the obovate shape of fruits and the irregular indumentum. Fruit length 7–8.5 mm long, 3.5–4.5 mm wide. Norway, Svalbard. Photograph by R. Elven. • Close-up of infructescence. Flowering inflorescence (infructescence). Fruits ovoid, brown, with drab-olive tones, 7–8.5 mm long, 3.5–4.5 mm wide, hairy, with sparse, short, simple hairs, almost no style persisting. Nunavut, Ellesmere Island, growing on a damp rocky slope. J.H. Soper 8311. 4 August, 1958. CAN 183638. • Close-up of fruits and seeds. Outer fruit wall with sparse straight hairs and only the suggestion of where the style had been. Ovoid inner wall, rounded in outline, bearing seeds that have longer stalks than other species. Nunavut, Axel Heiberg Island, plant growing in eroded Drepanocladus peat. Beschel 10823. 12 July, 1960. CAN 267674. • 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..