Draba alpina |
Draba platycarpa |
|
---|---|---|
alpine Draba |
broad-pod whitlow-grass, broadpod Draba |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Annuals; scapose or subscapose. |
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. |
often unbranched, sometimes branched proximally, (0.3–)0.5–3.2(–4) dm, densely hirsute proximally, trichomes simple, 0.9–1.5 mm, and stalked, 2–4-rayed, 0.1–0.6 mm, pubescent distally, trichomes usually branched, rarely simple ones present. |
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; petiole obscure; blade obovate to spatulate or oblanceolate, 1–4.5 cm × 5–25(–30) mm, margins dentate, surfaces pubescent, abaxially with stalked, (2 or) 3 or 4-rayed trichomes, 0.1–0.6 mm, adaxially with simple, 0.7–1.3 mm, and stalked, 2–4-rayed ones, 0.1–0.5 mm. |
Cauline leaves | 0. |
(3 or) 4–8(–14); sessile; blade similar to basal. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
12–45(–60)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent, trichomes 2–4-rayed. |
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. |
(mid- and late-season ones cleistogamous, apetalous); sepals oblong, 1.4–2.2 mm, pubescent; petals white, oblanceolate, (1.7–)2.5–3.5(–4) × 1–2 mm; anthers ovate, 0.2–0.35 mm (shorter in cleistogamous flowers). |
Fruiting pedicels | ascending to divaricate-ascending, straight or, sometimes, slightly curved upwards, 4–14(–30) mm, pubescent, trichomes simple and 2–4-rayed. |
horizontal to divaricate, straight, 4–9(–11) mm, 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). |
obovate-oblong to obovate, plane, flattened, 5–8.2(–9.5) × (2.4–)2.8–3.7(–4) mm; valves pubescent, trichomes simple, antrorse, 0.2–0.5 mm; ovules (28–)40–70(–82) per ovary; style 0.01–0.2 mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
ovoid, 0.5–0.7 × 0.3–0.5 mm. |
2n | = 80. |
= 16, 32. |
Draba alpina |
Draba platycarpa |
|
Phenology | Flowering Jun–Aug. | Flowering Feb–Mar. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Rocky hillsides, gravelly and sandy areas, dry plains, roadsides |
Elevation | 0-1000 m (0-3300 ft) | 0-500 m (0-1600 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
|
AR; AZ; ID; LA; OK; OR; TX; WA
|
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 platycarpa is occasionally treated as a variety of D. cuneifolia, but is amply distinct from that species (R. L. Hartman et al. 1975). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 330. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | D. cuneifolia var. platycarpa, D. viperensis |
Name authority | Linnaeus: Sp. Pl. 2: 642. (1753) | Torrey & A. Gray: Fl. N. Amer. 1: 108. (1838) |
Web links |