Draba alpina |
Draba oblongata |
|
---|---|---|
alpine Draba |
Canadian arctic Draba |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; (cespitose); caudex branched (with persistent leaf remains); sometimes 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, (0.2–)0.4–1.5(–1.9) dm, pubescent throughout, trichomes simple, 0.4–0.8 mm, and short-stalked, 4–10-rayed, 0.05–0.3 mm, (mostly branched distally). |
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 base and margin ciliate, (trichomes simple, 0.3–1 mm); blade oblanceolate to lanceolate, 0.4–1.5 cm × 1.5–5 mm, margins entire, surfaces pubescent with simple and stalked, 2- or 3-rayed trichomes, 0.4–1 mm, with short-stalked, 8–12-rayed, stellate ones, 0.1–0.2 mm. |
Cauline leaves | 0. |
0–2; sessile; blade oblong to broadly ovate, margins entire, surfaces pubescent as basal. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
5–13(–18)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem distally. |
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, 2–3 mm, pubescent, (trichomes simple and short-stalked, mostly 2-rayed); petals white, spatulate to obovate, 3.5–5 × 1.5–2.5 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 to ascending, straight, 2–6(–8) 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). |
elliptic to oblong, plane, slightly flattened, 4–8(–9.5) × 2–3(–4) mm; valves pubescent, trichomes short-stalked, (2–)5–12-rayed, 0.05–3 mm; ovules 24–36 per ovary; style 0.2–0.8 mm (stigma considerably wider than style, often appearing 2-lobed). |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
ovate, 0.7–1 × 0.5–0.6 mm. |
2n | = 80. |
= 64. |
Draba alpina |
Draba oblongata |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Ridges and hillsides, sand and gravel flood plains, swales, tundra |
Elevation | 0-1000 m (0-3300 ft) | 0-400 m (0-1300 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
|
AK; NT; NU; Greenland; e Asia (Russian Far East, Siberia) |
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.) |
Plants of Draba oblongata are occasionally misidentified as decaploid (2n = 80) D. arctica, but the former is readily separated by a preponderance of simple (versus stellate) trichomes on both leaf blade surfaces. Draba oblongata is sometimes confused with D. micropetala, but the latter has pale yellow (versus white) flowers, fruits pubescent with simple and spurred (versus (2–)5–12-rayed) trichomes, and stigmas as wide as (versus much wider than) the style. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 323. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | D. arctica subsp. groenlandica, D. cinerea subsp. groenlandica, D. groenlandica |
Name authority | Linnaeus: Sp. Pl. 2: 642. (1753) | R. Brown ex de Candolle: Syst. Nat. 2: 342. (1821) |
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