Draba ventosa |
Draba petrophila |
|
---|---|---|
wind river Draba, wind river whitlow-grass |
Santa Rita Mountain Draba, Santa Rita Mountain whitlowgrass, Santa Rita whitlow grass |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves, branches creeping, sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose, long-lived); caudex simple or branched (covered with persistent petioles), not scapose. |
Stems | unbranched, (0.1–)0.2–0.4(–0.6) dm, densely pubescent throughout, trichomes 2–6-rayed, 0.1–0.6 mm. |
usually unbranched, rarely branched, 0.3–1.9(–2.8) dm, moderately to densely hirsute throughout, trichomes simple, 0.2–1.3 mm, with short-stalked to subsessile, cruciform, 0.02–0.4 mm, and 2-rayed ones, 0.3–0.9 mm. |
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 ciliate, (trichomes simple, 0.4–1.5 mm); blade oblanceolate, 1–5(–6) cm × 2–5(–10) mm, margins usually entire, rarely denticulate, surfaces pubescent, abaxially with stalked, cruciform trichomes, 0.07–0.5 mm, adaxially often similar, sometimes with fewer, simple and 2-rayed trichomes, 0.4–1.3 mm. |
Cauline leaves | 0. |
3–10; sessile; blade ovate to lanceolate or oblong, margins entire or denticulate, surfaces pubescent as basal. |
Racemes | 5–10(–16)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, densely pubescent as stem. |
10–37(–58)-flowered, ebracteate, 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 oblong, 2–3.5 mm, pubescent, (trichomes simple and 2-rayed); petals yellow, oblanceolate, 3.5–6 × 1.2–1.8 mm; anthers oblong, 0.8–1 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). |
divaricate-ascending, straight, 4–10 mm, pubescent throughout, trichomes simple (0.1–0.5 mm) and subsessile, 2–4-rayed, (0.03–0.2 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. |
lanceolate to elliptic, often strongly twisted, flattened, 5–11 × 2–3 mm; valves puberulent at least along margin, trichomes simple, antrorse, 0.03–0.15 mm; ovules 14–24 per ovary; style 0.8–1.8(–2.5) mm. |
Seeds | oblong, 1.4–1.9 × 0.9–1.2 mm. |
ovoid, 1–1.4 × 0.6–0.9 mm. |
2n | = 36. |
|
Draba ventosa |
Draba petrophila |
|
Phenology | Flowering Jul–Aug. | Flowering Jul–Sep. |
Habitat | Talus slopes and alpine tundra | Crevices, ledges of cliffs |
Elevation | 2000-4000 m (6600-13100 ft) | 1200-2800 m (3900-9200 ft) |
Distribution |
CO; UT; WY; AB; BC; YT |
AZ
|
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 petrophila is often broadly circumscribed to include the taxon herein called D. viridis. For a discussion of the differences between these species and the closely related D. helleriana, see I. A. Al-Shehbaz and M. D. Windham (2007). Draba petrophila, in the strict sense, is known only from Cochise, Pima, and Santa Cruz counties in southeastern Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 344. | FNA vol. 7, p. 329. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. helleriana var. blumeri, D. helleriana var. petrophila | |
Name authority | A. Gray: Amer. Naturalist 8: 212. (1874) | Greene: Pittonia 4: 17. (1899) |
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