Draba cinerea |
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gray-leaf Draba, gray-leaf whitlow-grass |
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Habit | Perennials; (cespitose); caudex simple or branched; rarely scapose. |
Stems | unbranched, (0.3–)0.5–1.6(–2.7) dm, pubescent throughout, trichomes 4–10-rayed, 0.1–0.3 mm, (often some rays branched, simple trichomes sparse, to 0.6 mm). |
Basal leaves | rosulate; petiolate; petiole base and proximalmost margin ciliate, (trichomes simple, 0.2–0.8 mm); blade oblanceolate to narrowly obovate or linear-lanceolate, 0.4–1.5 cm × 1–5 mm, margins usually entire, rarely with 1 tooth on each side, surfaces densely pubescent with minutely stalked, stellate, 8–12-rayed, trichomes 0.1–0.25 mm, (midvein obscure abaxially, apex trichomes simple). |
Cauline leaves | 0–3(–5); sessile; blade ovate or oblong to lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | (3–)5–17(–24)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals ovate, 1.7–2.5 mm, pubescent, (trichomes simple and short-stalked, 2- or 3-rayed); petals white, spatulate to obovate, 3.5–4.5 × 1.5–2 mm; anthers ovate, 0.3–0.4 mm. |
Fruiting pedicels | divaricate-ascending or ascending, straight, (3–)4–7(–9) mm, pubescent as stem. |
Fruits | oblong to elliptic, plane, slightly flattened, 5–8 × 2–3 mm; valves pubescent, trichomes short-stalked, 2–5-rayed, 0.05–0.3 mm, (some rays branched); ovules 20–36(–42) per ovary; style (0.1–)0.2–1 mm. |
Seeds | ovoid, 0.6–0.8 × 0.4–0.6 mm. |
2n | = 48. |
Draba cinerea |
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Phenology | Flowering Jun–Jul. |
Habitat | Rock outcrops, ridges, meadows, gravel beaches, stream banks, alluvial fans |
Elevation | 0-500 m (0-1600 ft) |
Distribution |
AK; BC; NT; NU; ON; QC; SK; YT; Greenland; Europe (Finland, Norway, n Russia); e Asia (Russian Far East, Siberia) |
Discussion | Draba cinerea is a polymorphic species in which tetraploid, hexaploid, heptaploid, and octoploid chromosome counts (all based on x = 8) have been reported (e.g., R. C. Rollins 1993). Although we have not seen the type collection, we tentatively consider the taxon to be hexaploid, which is the predominant ploidy level throughout the species range, including North America, and also from its type region in Siberia. Hexaploid Draba cinerea is closely related to decaploid (2n = 80) D. arctica, from which it is distinguished with difficulty. In general, D. cinerea has 1–3(–5)-leaved stems, basal leaf blades usually not terminated with simple trichomes and with obscure midveins abaxially, petals 3.5–4.5 mm, and seeds 0.6–0.8 × 0.4–0.6 mm. By contrast, D. arctica has leafless or 1(–3)-leaved stems, basal leaf blades terminated with simple or 2-rayed trichomes and with midveins distinct abaxially, petals 3.5–6 mm, and seeds (0.8–)0.9–1.1 × (0.6–)0.7–0.8 mm. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 300. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | |
Synonyms | D. magellanica subsp. cinerea |
Name authority | Adams: Mém Soc. Imp. Naturalistes Moscou 5: 103. (1817) |
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