Draba helleriana |
Draba oligosperma |
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Heller's Draba |
few-seed Draba, few-seed Draba whitlow-grass, few-seed whitlow-grass |
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Habit | Biennials or perennials; (short-lived); caudex simple or branched; not scapose. | Perennials; (cespitose, densely pulvinate); caudex branched (with persistent leaf bases, branches congested or somewhat creeping, sometimes terminating in sterile rosettes); scapose. |
Stems | branched, (0.1–)1.5–4.3(–5.1) dm, hirsute throughout, trichomes simple, 0.4–1.3(–1.8) mm, with short-stalked to subsessile, 3–5-rayed ones, 0.2–0.4 mm, (some slightly coarser, 2-rayed). |
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). |
Basal leaves | rosulate; petiolate; petiole base ciliate or not; blade oblanceolate to obovate, 0.9–4.1(–5.2) cm × 2–7(–10) mm, margins entire or dentate, surfaces pubescent, abaxially with stalked, cruciform, and fewer 3–5-rayed trichomes, 0.1–0.6 mm, adaxially with cruciform and simple trichomes, 0.4–1.3 mm, and smaller 2-rayed ones. |
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. |
Cauline leaves | (8–)12–31(–43); sessile; blade ovate to lanceolate or oblong, margins usually dentate, rarely subentire, surfaces pubescent as basal. |
0. |
Racemes | 10–52(–83)-flowered, usually ebracteate, rarely proximalmost 1 or 2 flowers bracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
4–12(–17)-flowered, ebracteate, elongated in fruit; rachis not flexuous, glabrous or pubescent as stem. |
Flowers | sepals oblong, 2.5–4 mm, pubescent, (trichomes simple and stalked, 2-rayed); petals yellow, oblanceolate, 5–7 × 1.5–2.2 mm; anthers oblong, 0.5–0.8 mm. |
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). |
Fruiting pedicels | horizontal to divaricate-ascending, straight or slightly curved upward, 4–10(–13) mm, pubescent as rachis abaxially, glabrous adaxially. |
divaricate-ascending, straight, (2–)3–10(–13) mm, glabrous or sparsely pubescent, trichomes pectinate. |
Fruits | (not appressed to rachis), lanceolate to ovate or oblong-lanceolate, slightly to strongly twisted or plane, flattened, 5–15 × 2–3.5 mm; valves puberulent, trichomes simple and subsessile, 2(–4)-rayed, 0.03–0.25(–0.8) mm; ovules 14–28 per ovary; style (1–)1.5–3.5 mm. |
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. |
Seeds | oblong, 1–1.3 × 0.6–0.8 mm. |
ovoid, 1.1–1.5 × 0.7–1 mm. |
2n | = 18. |
= 32, 64. |
Draba helleriana |
Draba oligosperma |
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Phenology | Flowering Jun–Sep. | Flowering May–Jul. |
Habitat | Oak and pine-fir woodlands, aspen groves, rocky meadows | Rock outcrops, talus, gravel benches, tundra |
Elevation | 2100-3600 m (6900-11800 ft) | 200-3900 m (700-12800 ft) |
Distribution |
AZ; CO; NM; Mexico (Nuevo León)
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AK; CA; CO; ID; MT; NV; OR; WY; AB; BC; NT; NU; YT
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Discussion | Draba helleriana is highly variable and was divided by C. L. Hitchcock (1941) into four varieties. For a discussion of those and the circumscription of the species, see I. A. Al-Shehbaz and M. D. Windham (2007). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 311. | FNA vol. 7, p. 324. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. aurea var. tylosa, D. helleriana var. leiocarpa, D. helleriana var. neomexicana, D. helleriana var. patens, D. helleriana var. pinetorum, D. neomexicana, D. neomexicana var. robusta, D. pallida, D. patens, D. pinetorum, D. stylosa | 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 |
Name authority | Greene: Pittonia 4: 17. (1899) | Hooker: Fl. Bor.-Amer. 1: 51. (1830) |
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