Draba alpina |
Draba trichocarpa |
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alpine Draba |
stanley creek Draba |
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Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; (cespitose, densely pulvinate); caudex branched (covered with persistent leaves, branches 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, 0.07–0.35 dm, pubescent throughout, trichomes (soft), stalked, subdendritic, (somewhat crisped), 0.1–0.5 mm, (simple ones absent). |
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 oblong to obovate, 0.2–0.4 cm × 0.5–1.5 mm, margins entire, (ciliate, trichomes simple and branched, subdendritic, or spurred, 0.3–0.8 mm), surfaces sparsely pubescent, abaxially with stalked, 4–6-rayed stellate trichomes, 0.1–0.4 mm, adaxially with simple and 4–6-rayed trichomes, mainly on distal 1/2. |
Cauline leaves | 0. |
0 (or 1); sessile; blade similar to basal. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
2–9-flowered, ebracteate, 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 ovate, 2–3 mm, pubescent, (trichomes short-stalked); petal color unknown, broadly obovate, 2–4 × 2–2.5 mm; anthers oblong, 0.5–0.6 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 to ascending, straight, 1–4.5 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). |
ovoid, plane, slightly inflated basally, flattened distally, 2–6 × 2–3.5 mm; valves densely pubescent, trichomes 4-rayed, 0.1–0.4 mm, (often some rays spurred or branched); ovules 4–10 per ovary; style 0.3–0.7 mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
oblong, 1.4–2 × 0.8–1.2 mm. |
2n | = 80. |
|
Draba alpina |
Draba trichocarpa |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Gravelly metamorphic soil at ecotone between sagebrush steppe and open conifer forests |
Elevation | 0-1000 m (0-3300 ft) | ca. 2000 m (ca. 6600 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
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ID |
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. Draba trichocarpa is an apomictic polyploid that appears to be closely related to D. novolympica. It is readily distinguished from that species by the primarily dendritic trichomes (and absence of simple trichomes) on the stems, pedicels, and fruits. Draba trichocarpa is known from the Stanley Basin of central Idaho (Custer County). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 344. |
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: Contr. Gray Herb. 214: 4. (1984) |
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