Draba scotteri |
Draba subumbellata |
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scotter's whitlowgrass |
mound Draba, parasol Draba |
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Habit | Perennials; (cespitose); caudex simple or branched (covered with persistent leaves); 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, 0.2–1.4 dm, pubescent throughout, trichomes 2–8-rayed, 0.07–0.4 mm, and, sometimes, simple ones, 0.2–0.8 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 ciliate, (trichomes simple, 0.2–1 mm); blade oblanceolate, 0.4–1.5 cm × 1–3 mm, margins entire, (ciliate as petiole base), surfaces pubescent with short-stalked, stellate, 8–12-rayed trichomes, 0.1–0.4 mm. |
(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 | 1–9-flowered, usually ebracteate, rarely proximalmost flower subtended by a tiny bract, usually 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 oblong, 2–3 mm, subapically pubescent, (trichomes simple); petals yellow, obovate to spatulate, 3.5–5.5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 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 | divaricate-ascending, straight, 3–8(–12) mm, pubescent as stem. |
divaricate-ascending, straight, 1.5–3(–6) mm, glabrous or pubescent as stem. |
Fruits | lanceolate to narrowly so, plane, flattened, 5–11 × 1.5–2.5 mm; valves pubescent, trichomes simple, 0.1–0.4 mm, occasionally with some 2-rayed ones; ovules 12–18 per ovary; style 0.3–1 mm. |
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 | ovoid, 0.8–1.2 × 0.6–0.7 mm. |
oblong, 1–1.2 × 0.5–0.7 mm. |
2n | = 96. |
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Draba scotteri |
Draba subumbellata |
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Phenology | Flowering Jun–Jul. | Flowering Jul–Aug. |
Habitat | Talus and gravelly summits in alpine communities | Wind-eroded areas, alpine fellfields, rock crevices |
Elevation | 1200-2000 m (3900-6600 ft) | 3300-4100 m (10800-13500 ft) |
Distribution |
YT |
CA; NV |
Discussion | Of conservation concern. The description of Draba scotteri is based on collections from Kluane National Park, southwestern Yukon Territory. (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. 335. | FNA vol. 7, p. 343. |
Parent taxa | ||
Sibling taxa | ||
Name authority | G. A. Mulligan: Canad. J. Bot. 57: 1874. (1979) | Rollins & R. A. Price: Aliso 12: 25, figs. 1k–n, 4. (1988) |
Web links |