Draba alpina |
Draba subalpina |
|
---|---|---|
alpine Draba |
subalpine Draba |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; (cespitose); caudex simple or branched (with some persistent leaf bases); 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. |
unbranched, 0.3–1(–1.3) dm, often glabrous throughout, sometimes sparsely pubescent proximally, trichomes simple and stalked, 2-rayed, 0.2–1 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; sessile; blade (fleshy), oblanceolate to linear, (0.4–)0.5–1.4(–2) cm × (1–)1.5–3(–4) mm, margins entire, (ciliate at least apically, trichomes simple and 2-rayed), surfaces usually glabrous, rarely sparsely pubescent with simple and stalked, 2- (or 3-)rayed trichomes, 0.2–1 mm, (midvein obscure). |
Cauline leaves | 0. |
0. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
(6–)10–28(–40)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous. |
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 broadly ovate, 1.7–2.5 mm, usually glabrous, rarely pubescent, (trichomes simple and short-stalked, 2-rayed); petals white, spatulate to obovate, 3–5 × 2–3 mm; anthers oblong, 0.5–0.7 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, (3–)5–10(–17) mm, glabrous. |
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). |
ovoid to lanceolate, plane, inflated at least basally, 4–8(–10) × 2.5–4 mm; valves glabrous or sparsely puberulent, trichomes simple, 0.02–0.1 mm; ovules 6–12 per ovary; style 0.2–0.9 mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
ovoid, 1–1.5 × 0.7–1.1 mm. |
2n | = 80. |
= 26. |
Draba alpina |
Draba subalpina |
|
Phenology | Flowering Jun–Aug. | Flowering May–Jun. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Rocky knolls and marly limestone soil in pine-oak-juniper woodlands, edges of spruce-fir forests |
Elevation | 0-1000 m (0-3300 ft) | 1800-3400 m (5900-11200 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
|
UT
|
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.) |
Molecular studies (M. A. Beilstein and M. D. Windham 2003) and chromosomal data (Windham 2000, 2004) suggest that Draba subalpina is most closely related to D. cusickii and D. sobolifera. From those, it is easily distinguished by having white (versus yellow) petals, glabrous (versus pubescent) rachises and stems distally, and glabrous or, rarely, sparsely pubescent (versus always pubescent) abaxial leaf blade surfaces. Draba subalpina is known from Garfield, Iron, Kane, and Wayne counties in south-central Utah. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 342. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | |
Name authority | Linnaeus: Sp. Pl. 2: 642. (1753) | Goodman & C. L. Hitchcock: Ann. Missouri Bot. Gard. 19: 77. (1932) |
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