Draba oligosperma |
Draba globosa |
|
---|---|---|
few-seed Draba, few-seed Draba whitlow-grass, few-seed whitlow-grass |
beavertip Draba, rockcress Draba, round-fruit Draba |
|
Habit | Perennials; (cespitose, densely pulvinate); caudex branched (with persistent leaf bases, branches congested or somewhat creeping, sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. |
Stems | unbranched, (0.1–)0.2–0.6(–1) dm, glabrous throughout or pubescent, trichomes sessile, pectinate, 0.1–0.3 mm, (their length parallel to long axis of stem). |
unbranched, 0.1–0.5 dm, glabrous. |
Basal leaves | rosulate; sessile; blade linear to linear-oblanceolate, (0.2–)0.4–1.1(–1.5) cm × 0.4–1.5(–1.8) mm, margins entire, (not or, rarely, ciliate, trichomes simple, 0.2–0.4 mm), surfaces pubescent with sessile, pectinate trichomes, 0.1–0.4 mm, (their long axis parallel to prominent abaxial midvein), sometimes glabrous adaxially. |
rosulate; sessile; blade (not fleshy), narrowly oblanceolate or lanceolate to linear, (0.2–)0.3–0.8 cm × 0.5–1.6(–2) mm, margins entire (ciliate, trichomes simple, 0.1–0.8 mm, apex acute, trichomes usually longer), surfaces glabrous, (midvein obscure abaxially). |
Cauline leaves | 0. |
0. |
Racemes | 4–12(–17)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. |
2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
Flowers | sepals ovate, 1.5–3 mm, glabrous or sparsely pubescent, (trichomes pectinate, 2-rayed, or simple); petals usually yellow, rarely creamy white, obovate, 2.5–4 × 1.5–3 mm; anthers ovate, 0.4–0.5 mm, (not producing pollen). |
sepals (persistent to near fruit maturity), ovate to broadly oblong, 2–3 mm, glabrous; petals white to pale yellow, obovate, 2.5–4 × 1.2–2 mm; anthers oblong, 0.4–0.6 mm. |
Fruiting pedicels | divaricate-ascending, straight, (2–)3–10(–13) mm, glabrous or sparsely pubescent, trichomes pectinate. |
divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
Fruits | ovoid to lanceolate, plane, inflated at least basally, sometimes slightly flattened distally, 3–6(–7) × 2–3.5(–4) mm; valves usually puberulent, rarely glabrous, trichomes simple and sessile, often unequally 2-rayed, 0.07–0.35 mm; ovules 6–12 per ovary; style 0.1–0.8(–1.1) mm. |
ovate, plane, flattened, 4.5–8 × 2.5–4 mm; valves (distinctly veined), glabrous; ovules 8–16 per ovary; style (0.1–)0.2–0.6 mm. |
Seeds | ovoid, 1.1–1.5 × 0.7–1 mm. |
oblong, 1.1–1.4 × 0.8–1 mm. |
2n | = 32, 64. |
|
Draba oligosperma |
Draba globosa |
|
Phenology | Flowering May–Jul. | Flowering Jun–Aug. |
Habitat | Rock outcrops, talus, gravel benches, tundra | Ridges, talus, alpine tundra and meadows |
Elevation | 200-3900 m (700-12800 ft) | 2700-3900 m (8900-12800 ft) |
Distribution |
AK; CA; CO; ID; MT; NV; OR; WY; AB; BC; NT; NU; YT
|
ID; MT; UT; WY
|
Discussion | Draba oligosperma is a highly variable and widespread species that has been shown to be apomictic (G. A. Mulligan and J. N. Findlay 1970; Mulligan 1972). It has been divided into species and infraspecific taxa by previous authors; the variation is continuous in every character; there are no clear geographical and morphological patterns that support its division. For characteristics separating D. oligosperma from the closely related D. pectinipila, see 80. D. pectinipila. Draba andina (Nuttall) A. Nelson (1899), not Philippi (1858) is an illegitimate name, sometimes found in synonymy under D. oligosperma. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba globosa is an apomictic species closely related to D. burkei (M. D. Windham, unpubl.). Though often treated as a variety of D. densifolia, it is morphologically and phyletically distinct from that species. Both R. C. Rollins (1993) and N. H. Holmgren (2005b) indicated that the species occurs in Colorado, but we have not seen material for that state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 324. | FNA vol. 7, p. 308. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. calcifuga, D. oligosperma var. andina, D. oligosperma var. leiocarpa, D. oligosperma var. microcarpa, D. oligosperma var. saximontana, D. oligosperma subsp. subsessilis, D. oligosperma var. subsessilis, D. saximontana, D. subsessilis | D. apiculata, D. densifolia var. apiculata, D. densifolia var. decipiens, D. densifolia var. globosa |
Name authority | Hooker: Fl. Bor.-Amer. 1: 51. (1830) | Payson: Amer. J. Bot. 4: 257. (1917) |
Web links |
|