Draba ventosa |
Draba oxycarpa |
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wind river Draba, wind river whitlow-grass |
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Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves, branches creeping, sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose); caudex branched (covered with persistent petiole remains); scapose. |
Stems | unbranched, (0.1–)0.2–0.4(–0.6) dm, densely pubescent throughout, trichomes 2–6-rayed, 0.1–0.6 mm. |
unbranched, 0.2–1.1 dm, pubescent proximally, trichomes short-stalked, 2–5-rayed, 0.1–0.5 mm, (some rays spurred). |
Basal leaves | (imbricate); rosulate; subsessile; petiole base and margin not ciliate; blade obovate to oblanceolate, (0.4–)0.5–1 cm × 1.5–4.5 mm, margins entire, surfaces densely pubescent with stalked, 2–6-rayed trichomes, (0.1–)0.2–0.9 mm. |
rosulate; petiolate; petiole base and margin ciliate, (trichomes simple, 0.3–1 mm); blade oblanceolate to lanceolate, 0.8–2.2 cm × 2–6 mm, margins often entire, surfaces pubescent abaxially with stalked, 2–5-rayed, stellate trichomes, 0.1–0.4 mm, often some rays spurred and trichomes appearing subdendritic, rarely glabrate, or with simple and 2-rayed ones, (midvein obscure abaxially, not thickened), adaxially glabrous or sparsely pubescent with simple trichomes, sometimes with long-stalked, 2- or 3-rayed ones. |
Cauline leaves | 0. |
0. |
Racemes | 5–10(–16)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, densely pubescent as stem. |
(2–)4–13-flowered, ebracteate, (subcorymbose), not elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals broadly ovate, 2–2.5 mm, pubescent, (trichomes short-stalked, 2–6-rayed); petals yellow, obovate, 3.5–5.5 × 1.5–3 mm; anthers oblong, 0.5–0.6 mm. |
sepals (grayish white), ovate to broadly so, 2.5–3 mm, pubescent, (trichomes simple and stalked, 2-rayed); petals creamy white to yellow, broadly obovate, 3.5–5 × 2.5–3.5 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | horizontal to divaricate-ascending, straight or slightly curved upward, 2–7(–9) mm, densely pubescent, trichomes 2–6-rayed, (0.1–0.6 mm). |
subhorizontal to divaricate-ascending (not appressed to rachis), often slightly curved upward, 4–7(–10) mm, pubescent, trichomes simple (0.4–1 mm), and 2–4-rayed (0.1–0.4 mm). |
Fruits | suborbicular to broadly ovate, plane, inflated basally, flattened distally, 4–7.5(–9) × 3.5–5 mm; valves densely pubescent, trichomes short-stalked, 2–6-rayed, 0.15–0.5 mm; ovules 8–12 per ovary; style (0.5–)0.7–1.4 mm. |
ovate to ovate-oblong, plane, flattened, 5–10 × 3–5 mm; valves puberulent along replum, trichomes simple, 0.1–0.3 mm; ovules (16–)18–28 per ovary; style 0.2–0.6 mm (stigma as wide as style). |
Seeds | oblong, 1.4–1.9 × 0.9–1.2 mm. |
(black), ovoid, 1–1.3 × 0.6–0.8 mm. |
2n | = 36. |
= 64. |
Draba ventosa |
Draba oxycarpa |
|
Phenology | Flowering Jul–Aug. | Flowering Jun–Jul. |
Habitat | Talus slopes and alpine tundra | Rocky soils |
Elevation | 2000-4000 m (6600-13100 ft) | |
Distribution |
CO; UT; WY; AB; BC; YT |
Greenland; Europe (Norway [including Spitsbergen], Sweden); Atlantic Islands (Iceland) |
Discussion | G. A. Mulligan (1971b) first reported apomixis in Draba ventosa based on studies of Canadian populations. This has now been confirmed in one of the southernmost populations (Duchesne County, Utah; M. D. Windham, unpubl.) as well. The species is easily overlooked and the large geographic gap between the Canadian and United States populations is likely to be narrowed or eliminated by additional collecting in western Montana. The limits of this species were expanded by C. L. Hitchcock (1941) to include D. ruaxes, but there are clear differences between them that support their recognition as distinct species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba oxycarpa is an octoploid that most closely resembles the decaploid D. alpina. It is distinguished from that species by having creamy white to pale yellow (versus bright yellow) petals, gray-green (versus purplish tinged) sepals, petals 2.5–3.5 (versus 1.7–2.5) mm wide, stems pubescent proximally with primarily branched (versus primarily simple) trichomes, nearly black (versus pale brown) seeds, and ovate to ovate-oblong (versus elliptic) fruits 3–5 (versus 2–3) mm wide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 344. | FNA vol. 7, p. 325. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. alpina var. oxycarpa, D. gredinii | |
Name authority | A. Gray: Amer. Naturalist 8: 212. (1874) | Sommerfelt: Mag. Naturvidensk., n. s. 1: 240. (1833) |
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