Draba alpina |
Draba brachystylis |
|
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alpine Draba |
shortstyle Draba |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Annuals or perennials; (short-lived); caudex often simple (poorly developed); 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. |
unbranched or branched, 0.6–3(–3.7) dm, pubescent throughout, trichomes simple, 0.4–0.9 mm, and 2–4-rayed, 0.05–0.4 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; subsessile; petiole base ciliate, (trichomes simple, 0.3–0.9 mm); blade oblanceolate, 1–3.5 cm × 4–7(–12) mm, margins entire or denticulate, surfaces pubescent, abaxially with stalked, (2–)4-rayed trichomes, 0.1–0.5 mm, adaxially with simple trichomes, 0.2–0.6 mm, with smaller, 2–4-rayed ones. |
Cauline leaves | 0. |
(1 or) 2–6(–8); sessile; blade lanceolate or oblanceolate to ovate, margins entire or denticulate, surfaces pubescent as basal. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
(5–)10–35(–47)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
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 ovate, 2–2.7 mm, pubescent, (trichomes simple and short-stalked, 2-rayed); petals pale yellow (fading white), oblanceolate, 2.5–3.7 × 0.9–1.2 mm; anthers ovate, 0.2–0.3 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 or only slightly curved upward, (1.5–)3–8(–10) mm, pubescent throughout, trichomes simple and stalked, 2–4-rayed. |
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). |
narrowly elliptic to lanceolate, plane, flattened, (7–)10–16(–19) × 2–3.5 mm; valves pubescent, trichomes simple, spurred, and short-stalked, 2-rayed, 0.05–0.2(–0.3) mm; ovules 20–36(–42) per ovary; style 0.2–0.6(–0.8) mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
oblong, 0.9–1.3 × 0.6–0.7 mm. |
2n | = 80. |
= 44. |
Draba alpina |
Draba brachystylis |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Fir and aspen communities, moist areas on rocky slopes |
Elevation | 0-1000 m (0-3300 ft) | 1700-3000 m (5600-9800 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.) |
Of conservation concern. Based on morphological and chromosomal data (L. Allphin and M. D. Windham, unpubl.), Draba brachystylis is hypothesized to be an allopolyploid derived through hybridization between D. albertina and D. santaquinensis. It is known to us only from Cache, Duchesne, Juab, Salt Lake, and Utah counties. C. L. Hitchcock (1941) indicated that the species grows in the Charleston Mountains of Clark County, Nevada, but we have not seen unequivocal material of it from that area. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 297. |
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) | Rydberg: Bull. Torrey Bot. Club 29: 240. (1902) |
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