Draba scotteri |
Draba cinerea |
|
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scotter's whitlowgrass |
gray-leaf Draba, gray-leaf whitlow-grass |
|
Habit | Perennials; (cespitose); caudex simple or branched (covered with persistent leaves); scapose. | Perennials; (cespitose); caudex simple or branched; rarely scapose. |
Stems | unbranched, 0.2–1.4 dm, pubescent throughout, trichomes 2–8-rayed, 0.07–0.4 mm, and, sometimes, simple ones, 0.2–0.8 mm. |
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 ciliate, (trichomes simple, 0.2–1 mm); blade oblanceolate, 0.4–1.5 cm × 1–3 mm, margins entire, (ciliate as petiole base), surfaces pubescent with short-stalked, stellate, 8–12-rayed trichomes, 0.1–0.4 mm. |
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. |
0–3(–5); sessile; blade ovate or oblong to lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | 1–9-flowered, usually ebracteate, rarely proximalmost flower subtended by a tiny bract, usually considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
(3–)5–17(–24)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals oblong, 2–3 mm, subapically pubescent, (trichomes simple); petals yellow, obovate to spatulate, 3.5–5.5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
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, straight, 3–8(–12) mm, pubescent as stem. |
divaricate-ascending or ascending, straight, (3–)4–7(–9) mm, pubescent as stem. |
Fruits | lanceolate to narrowly so, plane, flattened, 5–11 × 1.5–2.5 mm; valves pubescent, trichomes simple, 0.1–0.4 mm, occasionally with some 2-rayed ones; ovules 12–18 per ovary; style 0.3–1 mm. |
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, 0.8–1.2 × 0.6–0.7 mm. |
ovoid, 0.6–0.8 × 0.4–0.6 mm. |
2n | = 96. |
= 48. |
Draba scotteri |
Draba cinerea |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Jul. |
Habitat | Talus and gravelly summits in alpine communities | Rock outcrops, ridges, meadows, gravel beaches, stream banks, alluvial fans |
Elevation | 1200-2000 m (3900-6600 ft) | 0-500 m (0-1600 ft) |
Distribution |
YT |
AK; BC; NT; NU; ON; QC; SK; YT; Greenland; Europe (Finland, Norway, n Russia); e Asia (Russian Far East, Siberia) |
Discussion | Of conservation concern. The description of Draba scotteri is based on collections from Kluane National Park, southwestern Yukon Territory. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 335. | FNA vol. 7, p. 300. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. magellanica subsp. cinerea | |
Name authority | G. A. Mulligan: Canad. J. Bot. 57: 1874. (1979) | Adams: Mém Soc. Imp. Naturalistes Moscou 5: 103. (1817) |
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