Draba oligosperma |
Draba aprica |
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few-seed Draba, few-seed Draba whitlow-grass, few-seed whitlow-grass |
hairy Draba, openground Draba |
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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 branched distally, (0.3–)0.7–3(–3.6) dm, pubescent throughout, trichomes short-stalked to subsessile, cruciform, 0.1–0.5 mm. |
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. |
not rosulate; petiolate; petiole (to 1 cm), ciliate throughout; blade obovate to spatulate or ovate to suborbicular, 0.6–2.5 cm × 3–10 mm, margins usually entire, rarely toothed, surfaces pubescent with stalked, cruciform trichomes, 0.1–0.5 mm. |
Cauline leaves | 0. |
(5–)8–20(–25); sessile; blade oblong to lanceolate, margins entire, (not ciliate), surfaces pubescent as basal. |
Racemes | 4–12(–17)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. |
7–46-flowered, ebracteate, elongated in fruit, (lateral racemes from axils of distalmost leaves subumbellate); 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 ones cleistogamous, apetalous); sepals oblong, 0.6–1.2 mm, pubescent; petals white, spatulate, 1.3–2.5 × 0.5–1 mm; anthers ovate, 0.1–0.2(–0.05 in cleistogamous flowers) mm. |
Fruiting pedicels | divaricate-ascending, straight, (2–)3–10(–13) mm, glabrous or sparsely pubescent, trichomes pectinate. |
horizontal to divaricate-ascending, straight, 2–5 mm, pubescent, trichomes subsessile, 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. |
linear-ellipsoid to ellipsoid, plane, flattened, (3–)4–6 × 0.8–1.1 mm; valves pubescent, trichomes subsessile, (2–)4-rayed, 0.03–0.12 mm; ovules 4–6(–8) per ovary; style 0.07–0.13 mm. |
Seeds | ovoid, 1.1–1.5 × 0.7–1 mm. |
ovoid, 0.9–1.1 × 0.5–0.6 mm. |
2n | = 32, 64. |
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Draba oligosperma |
Draba aprica |
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Phenology | Flowering May–Jul. | Flowering Mar–May. |
Habitat | Rock outcrops, talus, gravel benches, tundra | Open knolls, rocky roadsides, rock outcrops, igneous glades, woods, alluvial areas near streams |
Elevation | 200-3900 m (700-12800 ft) | 100-400 m (300-1300 ft) |
Distribution |
AK; CA; CO; ID; MT; NV; OR; WY; AB; BC; NT; NU; YT
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AR; GA; MO; OK; SC
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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.) |
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Source | FNA vol. 7, p. 324. | FNA vol. 7, p. 290. |
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. brachycarpa var. fastigiata |
Name authority | Hooker: Fl. Bor.-Amer. 1: 51. (1830) | Beadle: in J. K. Small, Fl. S.E. U.S. ed. 2, 1336, 1375. (1913) |
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