Draba alpina |
Draba subumbellata |
|
---|---|---|
alpine Draba |
mound Draba, parasol Draba |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; (cespitose, densely pulvinate); caudex branched (densely covered with persistent leaves and remains, branches tightly grouped, sometimes terminating in sterile rosettes); 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, (0.05–)0.1–0.25 dm, densely pubescent throughout, trichomes (grayish), stalked, dendritic, 5–12-rayed, 0.1–0.25 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. |
(densely imbricate); rosulate; sessile; blade obovate to broadly oblong, 0.2–0.4 cm × 0.6–1.5 mm, margins entire, (not ciliate), surfaces densely pubescent, trichomes (grayish), stalked, dendritic, 5–12-rayed, 0.1–0.3 mm, (sometimes with long-stalked and spurred trichomes adaxially). |
Cauline leaves | 0. |
0. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
2–5(–10)-flowered, ebracteate, subumbellate or slightly 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 broadly oblong, 1.8–2.8 mm, pubescent, (trichomes dendritic); petals yellow, spatulate, 2.8–4 × 1–1.5 mm; anthers ovate, 0.3–0.4 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, 1.5–3(–6) mm, glabrous or pubescent as stem. |
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 ovoid-lanceolate, plane, inflated and sometimes subgibbous basally, flattened distally, 2–5 × 2–3 mm; valves pubescent, trichomes short-stalked, dendritic, 4–12-rayed, (sometimes spurred), 0.05–0.2 mm; ovules 6–12 per ovary; style 0.2–0.6 mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
oblong, 1–1.2 × 0.5–0.7 mm. |
2n | = 80. |
|
Draba alpina |
Draba subumbellata |
|
Phenology | Flowering Jun–Aug. | Flowering Jul–Aug. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Wind-eroded areas, alpine fellfields, rock crevices |
Elevation | 0-1000 m (0-3300 ft) | 3300-4100 m (10800-13500 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
|
CA; NV |
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 subumbellata is similar to, and sympatric with, D. oligosperma. It is distinguished from the latter by having stalked, stellate to dendritic leaf trichomes, subumbellate racemes, fruiting pedicels 1.5–3.0(–6.0) mm, fruits pubescent with mostly 4–12-rayed trichomes, and well-formed anthers and pollen. By contrast, D. oligosperma has sessile or subsessile, pectinately-branched leaf trichomes, elongated racemes, fruiting pedicels (2–)3–10(–13) mm, fruits glabrous or pubescent with simple and 2-rayed trichomes, and abortive anthers and/or pollen. Draba subumbellata is restricted to the White Mountains (Esmeralda County, Nevada, and Mono County, California) and to Coyote Ridge in the Sierra Nevada (Inyo County, California). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 343. |
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) | Rollins & R. A. Price: Aliso 12: 25, figs. 1k–n, 4. (1988) |
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