Draba oligosperma |
Draba rectifructa |
|
---|---|---|
few-seed Draba, few-seed Draba whitlow-grass, few-seed whitlow-grass |
mountain Draba |
|
Habit | Perennials; (cespitose, densely pulvinate); caudex branched (with persistent leaf bases, branches congested or somewhat creeping, sometimes terminating in sterile rosettes); scapose. | Annuals; not 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). |
(usually simple, rarely more, from base), unbranched or branched distally, (0.5–)0.7–3(–3.7) dm, pubescent, proximally trichomes simple and stalked, 2-rayed, 0.4–1.3 mm, with 3- or 4-rayed ones, 0.05–0.2 mm, distally trichomes stalked and 2–4-rayed. |
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; petiole (obscure), margin ciliate, (trichomes simple, to 1.5 mm); blade oblanceolate to obovate, 1–2(–3) cm × 2–7(–10) mm, margins entire or subapically denticulate, surfaces pubescent, abaxially with simple, 0.6–1.3 mm, and stalked, 2–4-rayed trichomes, 0.1–0.8 mm, adaxially with simple and stalked, 2-rayed ones, 0.4–1.2 mm. |
Cauline leaves | 0. |
3–10(–17); sessile; blade lanceolate to ovate or oblong, margins entire, surfaces pubescent as basal. |
Racemes | 4–12(–17)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. |
(15–)20–51(–62)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
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). |
(late-season ones petaliferous); sepals oblong, 1.3–2 mm, pubescent, (trichomes simple); petals yellow (sometimes fading white), oblanceolate, 1.5–3 × 0.5–1 mm; anthers ovate, 0.2–0.3 mm. |
Fruiting pedicels | divaricate-ascending, straight, (2–)3–10(–13) mm, glabrous or sparsely pubescent, trichomes pectinate. |
horizontal to divaricate-ascending, straight or curved upward, (2–)3–8(–10) mm, pubescent, trichomes simple and stalked, 2–4-rayed. |
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. |
lanceolate, plane, flattened, 6–9(11) × 1.3–2.3 mm; valves pubescent, trichomes simple, antrorse, 0.1–0.2 mm; ovules 32–60 per ovary; style 0.01–0.1 mm. |
Seeds | ovoid, 1.1–1.5 × 0.7–1 mm. |
ovoid, 0.5–0.7 × 0.4–0.5 mm. |
2n | = 32, 64. |
= 24. |
Draba oligosperma |
Draba rectifructa |
|
Phenology | Flowering May–Jul. | Flowering Apr–Aug. |
Habitat | Rock outcrops, talus, gravel benches, tundra | Open forests, meadows, gravelly knolls, disturbed sites |
Elevation | 200-3900 m (700-12800 ft) | 1800-3200 m (5900-10500 ft) |
Distribution |
AK; CA; CO; ID; MT; NV; OR; WY; AB; BC; NT; NU; YT
|
AZ; CO; NM; UT |
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.) |
Although O. E. Schulz (1927), C. L. Hitchcock (1941), and R. C. Rollins (1993) indicated that Draba montana was published in 1879; the name was first and validly published in 1878, with a reference to Rothrock’s description of a misapplied Linnaean name (D. nemorosa), which cited specimens that served as Watson’s type collection. Populations of D. rectifructa from northern Utah often grow with D. albertina and there is some evidence of hybridization. The only published chromosome count for D. rectifructa (M. D. Windham 2000) is identical to that of D. albertina and was derived from one of these mixed populations. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 324. | FNA vol. 7, p. 333. |
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. montana |
Name authority | Hooker: Fl. Bor.-Amer. 1: 51. (1830) | C. L. Hitchcock: Revis. Drabas W. N. Amer., 110. (1941) |
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