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 alpina L.

English: Alpine whitlowgrass,

French: Drave alpine.

Brassicaceae (Cruciferae), Draba family.

Published in Sp. Pl. 642. 1753.

Type: Northern Scandinavia: "Lapp", selected by Elven, in Jonsell and Jarvis, in press. Lectotype: LINN 823.5.

Synonymy.

Vegetative morphology. Plants 5–20 cm high; perennial herbs; caespitose. Taproot present. Caudex present. Aerial stems erect. Aerial stem trichomes spreading, or erect. Leaves basal in a rosette (comparatively large, broad and often dentate); alternate, or whorled; marcescent (there may be a thick accumulation of marcescent leaves). Petioles absent. Leaf blades simple. Leaf blade bases attenuate. Leaves not grass-like. Blades 7–18 mm long, 2–4 mm wide, linear, appearing single-veined. Blade adaxial surface hairy, hairs stellate, simple, and branched, hairs sparse, hairs white, or translucent. Blade abaxial surface hairy (with simple and irregularly branched hairs; some Hudson Bay plants have numerous small, stellate hairs), hairs villous, hairs moderately dense, hairs white, hairs irregularly branched, hairs spreading. Blade margins entire, with non-glandular hairs (that are short, thin and simple); apices acute (usually), or obtuse.

Reproductive morphology. Flowering stems two or more per plant; without leaves. Flowering stem hairs simple, or branched (with 1 or more irregular branches); shorter than the diameter of the flowering stem (some longer hairs more than 0.5 mm long); white or translucent. Inflorescences racemose; globose or sub-globose, or ovate, or lanceolate (as fruit matures); (8–)10–25 cm long; elongating as the fruit matures (with regularly spaced fruits). Pedicels glabrous, or with non-glandular hairs. Flowers per inflorescence 4–10(–18) (middle-sized for a Draba); medium-sized. Sepals conventional; 4; free; 1–1.3 mm long; (2–)2.5–3(–4) mm wide; purple (predominantly), or green (ovate-obovate); herbaceous. Calyx glabrous, or hairy (sparsely). Calyx hairs non-glandular (straight and unbranched); white or translucent. Petals conventional; free; 4; yellow (bright yellow); obovate, or spatulate; slightly lobed or undulating; (3–)3.5–5.5 mm long (flowers almost always only half open, cf. D. corymosa where they open completely); 3–4 mm wide (relatively narrow and tapering gradually to 0.6–0.7 mm wide at the base). Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous. Anthers yellow; sub-globose; 0.7–0.9 mm long. Ovary superior; carpels 2; syncarpous. Ovaries ovate; hairy. Styles 1; completely fused; 0.6–8 mm long; straight. Stigmas per ovary 1(–2). Placentation parietal. Ovules per ovary 16–20. Fruit stalked; stalk 6–12 mm long (distinctly curved); dry; a silique; ovoid, or oblong; purple (when young), or green at maturity; 7–10 mm long; 2.5–2.8 mm wide; glabrous, or hairy (scattered, sparse); surface appearing veinless; 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 0.4–0.6 mm long (distinct but short). Seeds 16–20; 1–1.2 mm long; brown; surfaces smooth (at 10×), verrucose (slightly at 40×).

Chromosome information. 2n = 80.

2n = 80. Flovik (1940, Svalbard); Heilborn (1941, Greenland); Knaben and Engelskjøn (1967, Norway); Brochmann et al. (1993, Svalbard); Mulligan (2003).

Draba alpina s.s. has 2n = 80 and only that number. Rollins (1993) reported numbers, 2n = 64 and 2n = 120. These most probably belong to two other species, D. oxycarpa and D. corymbosa, respectively.

Ploidy levels recorded 10x.

Ecology and habitat. Substrates: ridges, along streams, tundra; imperfectly drained moist areas, seepage slopes; gravel, silt (scree in erosion gully (CAN 267676)); with low organic content, with high organic content.

North American distribution. Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Uncommon. Low Arctic. Arctic islands: Baffin, Southampton (Mansel (Mansfield)).

Northern hemisphere distribution. Amphi-Atlantic. Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Labrador – Hudson Bay, West Greenland, East Greenland.

General notes. Within the genus, this species has been placed in Ser. Alpinae Tolm. in Kom., Fl. SSSR, 8: 391.1929. The Draba alpina aggregate is composed of D. aleutica, D. alpina, D. corymbosa, D. glacialis, ?D. macounii, D. ochroleuca, D. oxycarpa, D. pohlei, and some others.

Typification of D. alpina is important because this name has been applied indiscriminately for most yellow-flowered drabas throughout the Arctic and sometimes applied contrary to both possible interpretations of Linnaeus' concept. The lectotypification reserves the name for the decaploid (2n = 80) entity, which since the time of Linnaeus has been considered under this name in the European and North Atlantic areas. In other areas, the name has sometimes been applied differently. The most evident case is Löve and Löve (1975), reserving the name 'D. alpina L. s.s.' for the octoploid level (2n = 64). Most of the octoploid reports that the Löves (Heilborn 1927, Jørgensen et al. 1958, Löve and Löve 1961d, Knaben and Engelskjøn 1967, Löve 1970a) refer to are D. oxycarpa Sommerf.

The distribution of D. alpina in the restricted (and Linnaean) meaning is unclear. Material from the North Atlantic area (northeastern Canada, Greenland, Svalbard, northern Fennoscandia, northern Russia) corresponds well with it. It is much more uncertain in northwestern America, Russian Far East, and Siberia. These problems cannot be solved without a circumpolar revision of the yellow-flowered drabas. Recently, Elven (personal communication 2007) has suggested that this species may be restricted to the eastern-most parts of the Canadian Arctic Archipelago, reaching Hudson Bay but not further west.

Brochmann et al. (1993) investigated 101 populations of Nordic Draba for chromosome numbers and crossing relationships. The chromosome data suggested that all the populations and species are homoploid. Draba alpina is a decaploid, and the complex is probably polyphyletic. The relationships found from crossing data largely agreed with those inferred from earlier published molecular data, but corresponded poorly to relationships inferred from morphology.

Brochmann (1992b) found that seed size and colour distinguished species in this complex. Brochmann et al. (1993) concluded that D. alpina is probably polyphyletic and that this complex and the morphologically similar polyploid D. oxycarpa do not have any diploid progenitors in common.

Illustrations. • Close-up of flowering plant. Flowering plant with last year's stems. Note the comparatively narrow, semi-erect petals. Norway, Svalbard, Sassen. 6 August, 1987. Photograph by R. Elven. Voucher in O. • Close-up of leaves. The upper and lower surfaces of the leaves are glabrous but have long trichomes around the margins. Nunvavut, Baffin Island, Iqaluit. Aiken and Mallory 02–007. CAN. • Surface view of flowers. Surface view of flowers to show 4 petals, six anthers and a capitate stigma. • Close-up of whole plant. Bright yellow flowers born on leafless flowering stems. Note caudex with less build-up of marcescent leaves than plants of D. corymbosa. Nunavut, Baffin Island, Nettilling Lake. J.D. Jacobs and L. Maus. 10 July, 1986. CAN 518820. • Close-up of flowering inflorescence. Racemose inflorescence flowering from the base up. At the apex are undeveloped flowers. Note flower sepals that are much shorter than the petals. Flowers almost always only half open, c.f. D. corymbosa where they open completely. Nunavut, Baffin Island, Nettilling Lake. Jacobs and Maus. 30 July, 1986. CAN 518823. • Close-up of previous inflorescence. Note flower sepals that are much shorter than the petals. Note characteristic shallow lobe in petals. Flowers almost always only half open, c.f. D. corymbosa where they open completely. Nunavut, Baffin Island, Nettilling Lake. Jacobs and Maus. CAN 518823. • Close-up of flowers. Drawing by Mrs. S. Bergh and Mrs. L. Barstad based on a collection from Svalbard, Nordenskiöld Land, Advent Bay, gyeardalen, 17 Jul. 1924. J. Lid. (as D. alpina, det. D. oxycarpa S. Bretten and A.A. Frisvoll 6 May 1981). (Could well be included as there are indications that this octoploid is circumpolar). 0 213267. With permission of the Botanical Museum University of Oslo, Norway. • Close-up of fruiting inflorescence. Inflorescence elongates as the fruit matures. Note the regularly spaced fruit on characteristically curved stalks. Nunavut, Melville Peninsula, Hall Beach. P.J. Webber. 27 August, 1963. CAN 296004. • Close-up of fruits. Fruits glabrous, or with sparse scattered hairs. Styles that persist on the fruit are distinctly short. Nunavut, Melville Peninsula, Hall Beach. P.J. Webber. 27 August, 1963. CAN 296004. • Close-up of mature fruits shedding seed. Image shows structure of a silique. Seeds are shed by the outer wall (valves) of the fruit falling off and leaving seeds attached at the edges of a transparent partition between the two carpels. Nunavut, Southampton Island. N. Polunin 2279. 22 August, 1936. CAN 61439. • 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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