Draba alpina |
Draba crassa |
|
---|---|---|
alpine Draba |
thickleaf Draba |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; (cespitose); caudex simple or branched (well-developed, with persistent leaf bases); not scapose. |
Stems | unbranched, (0.3–)0.5–1.7(–2.8) dm, pubescent throughout, trichomes simple and 2-rayed, 0.3–0.8 mm, with 3–5-rayed ones, 0.1–0.3 mm. |
(decumbent to ascending), unbranched, (0.4–)0.6–1.3(–1.5) dm, usually glabrous proximally, rarely sparsely pubescent, pubescent distally, trichomes simple and short-stalked, 2-rayed, (crisped), 0.1–0.6(–0.8) mm. |
Basal leaves | rosulate; petiolate; petiole base (not thickened), ciliate, (trichomes simple, 0.3–1 mm); blade oblanceolate to obovate or lanceolate to oblong, 0.8–3(–4.5) cm × 2.5–6(–9) mm, margins entire, surfaces abaxially pubescent with stalked, 2–4-rayed trichomes, 0.1–0.5 mm, with simple ones (midvein obscure, not thickened), adaxially glabrous or sparsely pubescent with simple and stalked, 2–4-rayed trichomes. |
rosulate; petiolate; petiole ciliate, (trichomes mostly simple, 0.3–0.8 mm); blade oblanceolate, 2–6(–7) cm × 2.5–8(–10) mm, margins entire, (pubescent as petiole), surfaces glabrous. |
Cauline leaves | 0. |
2–4(–6); sessile; blade ovate to oblong, margins entire, (ciliate, trichomes simple and stalked, 2-rayed). |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
(4–)8–20(–25)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent, trichomes simple and short-stalked, 2-rayed, (crisped), (0.1–0.8 mm). |
Flowers | sepals (purplish tinged), narrowly ovate, 2.5–3 mm, pubescent, (trichomes simple and fewer, stalked, 2-rayed); petals bright yellow, narrowly obovate, 3.5–5 × 1.7–2.5 mm; anthers ovate, 0.3–0.4 mm. |
sepals (green tinged purplish), ovate to oblong, 2–3(–3.3) mm, pubescent, (trichomes simple and 2-rayed); petals yellow, spatulate to subobovate, 3.5–5(–6) × (2–) 2.5–3.5(–4) mm; anthers ovate, 0.5–0.6 mm. |
Fruiting pedicels | ascending to divaricate-ascending, straight or, sometimes, slightly curved upwards, 4–14(–30) mm, pubescent, trichomes simple and 2–4-rayed. |
divaricate-ascending, straight, 5–10(–15) mm, pubescent as rachis. |
Fruits | elliptic, plane, flattened, 6–10 × 2–3 mm; valves glabrous or glabrescent, trichomes simple, (not confined to replum); ovules 12–24 per ovary; style 0.2–0.3 mm (stigma about as wide as style). |
lanceolate to ovate-lanceolate, slightly twisted, flattened, (7–)8–14 × 3–5 mm; valves glabrous; ovules 16–20 per ovary; style (0.4–)0.7–1.2(–1.5) mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
oblong, 1.2–1.7 × 0.8–1.1 mm. |
2n | = 80. |
= 24. |
Draba alpina |
Draba crassa |
|
Phenology | Flowering Jun–Aug. | Flowering Jul–Aug. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Rock outcrops and talus, alpine tundra, rocky meadows |
Elevation | 0-1000 m (0-3300 ft) | 2900-4300 m (9500-14100 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
|
CO; MT; NM; UT; WY
|
Discussion | The synonymy above includes two North American names overlooked by C. L. Hitchcock (1941) and R. C. Rollins (1993). Draba alpina was broadly delimited by O. E. Schulz (1927) and included 17 varieties, some of which (e.g., corymbosa, oxycarpa, pilosa) are recognized herein as distinct species. The name D. alpina was so misapplied that it was used for any circumpolar or alpine, scapose, yellow-flowered, perennial Draba. Various chromosome numbers (e.g., 2n = 64, 80, 112, 120; S. I. Warwick and I. A. Al-Shehbaz 2006) have been reported for the species. As circumscribed here, it has the narrow distribution outlined above and includes plants with 2n = 80. Reports of the species from Alaska, Canadian Northwest Territories and Yukon, Siberia, eastern Asia, Russian Far East, and the Central Asian republics are either suspect or very unlikely. The entire D. alpina complex (including the above three species, D. glacialis Adams, D. macounii, etc.) is in need of critical molecular, cytological, and morphological study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba crassa is easily recognized by its combination of fleshy, distinctly petiolate leaves with glabrous surfaces and mostly decumbent flowering/fruiting stems. N. H. Holmgren (2005b) indicated that it has 52 seeds per fruit (26 per locule), but in the plants we examined, the seed count did not exceed 20 per fruit. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 302. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | D. chrysantha var. crassa |
Name authority | Linnaeus: Sp. Pl. 2: 642. (1753) | Rydberg: Mem. New York Bot. Gard. 1: 182. (1900) |
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