Draba alpina |
Draba pedicellata |
|
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alpine Draba |
Cusick's Draba, rocky-slope Draba, rocky-slope whitlow-grass, stalk whitlow-cress |
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Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; (loosely cespitose); caudex branched (with persistent leaf bases, 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, (0.15–)0.3–1.3(–1.6) dm, pubescent proximally, glabrous or nearly so distally, trichomes 2- or 3-rayed and simple, 0.1–1 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; blade oblanceolate to obovate, 0.4–1.6(–2) cm × 2–4(–6) mm, margins entire, (not ciliate), surfaces pubescent with stalked, 2–4-rayed trichomes, 0.2–0.9 mm, rarely adaxially with simple trichomes, (midvein obscure abaxially). |
Cauline leaves | 0. |
0. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
3–20(–27)-flowered, ebracteate, slightly to considerably elongated in fruit; rachis straight or flexuous, usually glabrous, rarely pubescent, trichomes simple and 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. |
sepals broadly ovate, 1.8–2.5 mm, glabrous or pubescent, (trichomes simple and branched); petals yellow, spatulate, 3.5–5.5 × 1.5–2.2 mm; anthers ovate, 0.4–0.5 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 horizontal, straight or curved upward (expanded basally or not), 4–9(–13) mm, glabrous or pubescent, trichomes simple and 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). |
lanceolate to ellipsoid or ovoid, plane (not curved), inflated or slightly flattened, (4.2–)5.3–10(–13) × 2.5–4.5(–5.5) mm; valves glabrous or pubescent, trichomes simple and short-stalked, 2-rayed, 0.05–0.3 mm; ovules 8–16 per ovary; style 0.3–1(–1.2) mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
oblong, 1.2–1.6 × 0.7–0.9 mm. |
2n | = 80. |
= 20. |
Draba alpina |
Draba pedicellata |
|
Phenology | Flowering Jun–Aug. | Flowering May–Jul. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Rock outcrops, talus, steep gravel slopes in pinyon-juniper, mixed conifer, and subalpine meadow communities |
Elevation | 0-1000 m (0-3300 ft) | 2300-3800 m (7500-12500 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
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NV; UT
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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 pedicellata is known from Elko, Eureka, Nye, and White Pine counties in northeastern Nevada and to Tooele County in northwestern Utah. It was considered a variety of D. cusickii by R. C. Rollins (1993); chromosome number, morphology, and geographic distribution suggest a closer relationship to D. sphaeroides. For a detailed discussion and comparison of these species, consult M. D. Windham (2004). N. H. Holmgren (2005b) divided D. pedicellata into two varieties: var. pedicellata, which is found on limestone throughout the species range, and var. wheelerensis, which is found on non-calcareous substrates in White Pine County. Although var. wheelerensis has slightly more spreading pedicels on somewhat more flexuous rachises, it appears to be little more than a dwarf alpine form of the species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 328. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | D. cusickii var. pedicellata, D. pedicellata var. wheelerensis |
Name authority | Linnaeus: Sp. Pl. 2: 642. (1753) | (Rollins & R. A. Price) Windham: Madroño 50: 221. (2004) |
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