Draba arctogena |
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fellfield whitlowgrass |
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Habit | Perennials; (cespitose); caudex branched (sometimes with persistent leaf remains); sometimes scapose. |
Stems | unbranched, 0.3–1.4 dm, pubescent throughout, trichomes simple, 0.2–1 mm, and 2–6-rayed, 0.05–0.3 mm. |
Basal leaves | rosulate; petiolate; petiole base and margin ciliate, (trichomes mostly simple, 0.2–1 mm); blade oblanceolate to narrowly obovate, 0.4–1.7 cm × 1.5–6 mm, margins entire or with 1–3 teeth on each side, surfaces pubescent with primarily simple trichomes, 0.3–1mm, abaxially mixed with stalked, 4–10-rayed ones, 0.1–0.2 mm. |
Cauline leaves | 0 or 1; sessile; blade ovate to oblong, margins entire or toothed, surfaces pubescent as basal. |
Racemes | 2–14(–17)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals ovate, 1.8–2.5 mm, pubescent, (trichomes simple and short-stalked, 2–4-rayed); petals white, spatulate, 3–4 × 1.5–2 mm; anthers ovate, 0.3–0.4 mm. |
Fruiting pedicels | suberect to ascending, straight, 1–5(–7) mm, pubescent, trichomes simple and 2–4-rayed. |
Fruits | oblong, plane, flattened, 4–9 × 2–3.5 mm; valves pubescent, trichomes short-stalked, 2–4-rayed, 0.1–0.5 mm, sometimes with simple ones; ovules 20–32 per ovary; style 0.1–0.4 mm (stigma distinctly wider than style). |
Seeds | ovoid, 0.7–1 × 0.5–0.6 mm. |
2n | = 48. |
Draba arctogena |
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Phenology | Flowering Jun–Jul. |
Habitat | Scree, sandy hills, gravel flats |
Elevation | 0-450 m (0-1500 ft) |
Distribution |
NT; NU; Greenland |
Discussion | Draba arctogena is sometimes confused with D. norvegica, from which it differs by having less elongated fruiting racemes, abaxial leaf surfaces with 4–10-rayed (versus cruciform or, rarely, 2–6-rayed) trichomes, and fruits with 2–4-rayed trichomes, 0.1–0.5 mm, (versus glabrous or with simple and 2–4-rayed trichomes, 0.05–0.25 mm). The limits of D. arctica, D. arctogena, D. cinerea, and D. oblongata need to be critically evaluated in light of molecular and cytological data. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 292. |
Parent taxa | |
Sibling taxa | |
Synonyms | D. groenlandica var. arctogena, D. cinerea var. arctogena |
Name authority | (E. Ekman) E. Ekman: Svensk Bot. Tidskr. 25: 492. (1932) |
Web links |