Draba sibirica |
Draba simmonsii |
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Siberian whitlowgrass |
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Habit | Perennials; (stoloniferous); caudex branched (sparsely covered with persistent petiole remains, branches slender, creeping); scapose. | Perennials; caudex branched (with persistent leaf bases and petioles); scapose. |
Stems | (subdecumbent when sterile), unbranched, 0.5–2.5 dm, sparsely to densely hispid, trichomes malpighiaceous, (flowering scapes sparsely pilose proximally with simple trichomes, often glabrous on distal 1/2). |
unbranched, (0.15–)0.3–1.1(–1.3) dm, often pubescent throughout, sometimes sparsely pubescent distally, trichomes stalked, 2–4-rayed, and fewer, simple ones, 0.1–0.3(–0.6) mm. |
Basal leaves | rosulate; petiolate; blade oblong-lanceolate or oblanceolate, 0.4–2.2 cm × 1–5(–10) mm, margins entire, surfaces often pubescent, sometimes glabrous (except margins), with appressed, malpighiaceous trichomes (these sometimes with 1 or 2 shorter, lateral branches, appearing 3-fid or cross-shaped). |
(not imbricate); rosulate; petiolate; petiole (base somewhat thickened), margin ciliate, (trichomes simple, 0.5–1 mm); blade oblong to oblong-lanceolate, 0.5–1.6 cm × 2–5 mm, margins entire (apex subacute to obtuse), surfaces pubescent throughout or glabrous adaxially, with simple and stalked, 2–4(–6)-rayed, stellate to subdendritic trichomes. |
Cauline leaves | 0. |
0. |
Racemes | 7–20-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous (straight), glabrous. |
(2–)4–10(–14)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous (straight), pubescent as stem. |
Flowers | sepals (erect), oblong or ovate, 2–2.7 mm (lateral pair subsaccate basally), glabrous or abaxially sparsely pilose, (trichomes simple); petals yellow, narrowly obovate, 4–6 × 2–3 mm, (apex emarginate); anthers ovate-subcordate, 0.4–0.5 mm. |
sepals (purplish green), oblong, (2.5–)2.8–3.5(–3.8) mm, pubescent, (trichomes simple and sometimes short-stalked, 2-rayed); petals pale yellow, narrowly obovate, (sides non-parallel), (3.5–)3.8–5.5(–5.8) × (2.5–)2.8–4(–4.6) mm, (emarginate); anthers ovate, ca. 0.5 mm. |
Fruiting pedicels | divaricate, straight or curved, (often filiform), 5–18(–23) mm, glabrous. |
divaricate, straight, 2.5–10 mm, pubescent as stem. |
Fruits | usually oblong to elliptic, rarely sublinear, plane, flattened, 4–8 × 1.5–2.2 mm; valves glabrous, (obscurely veined); ovules 24–30 per ovary; style 0.5–1 mm. |
lanceolate, plane, slightly flattened, 5.5–9(–11) × 2.3–3.8 mm; valves pubescent, trichomes simple, sometimes with fewer, 2-rayed ones, 0.1–0.3 mm; ovules 16–24(–28) per ovary; style 0.1–0.3 mm (stigma as wide as style). |
Seeds | (brown), ovoid, 0.9–1.2 × 0.5–0.6 mm. |
(dark brown), oblong-ovate, 1–1.3 × 0.7–0.8 mm. |
2n | = 16. |
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Draba sibirica |
Draba simmonsii |
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Phenology | Flowering May–Jul. | Flowering late Jun–Jul. |
Habitat | Wet places on rocky slopes | Dry open ground, open patches in meadows or heath vegetation, outwash plains |
Elevation | 0-300 m (0-1000 ft) | 0-100 m (0-300 ft) |
Distribution |
Greenland; Europe (Russia); Asia (Caucasus, Iran, Russian Far East, Siberia, Turkey, central republics) |
NT; NU |
Discussion | Draba sibirica is one of three species of the genus in North America exhibiting malpighiaceous trichomes. It is easily distinguished from others (D. malpighiacea and some plants of D. spectabilis) by a complete absence of cauline leaves. It is found in the flora area in northeastern Greenland. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 7, p. 337. | FNA vol. 7, p. 337. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lepidium sibiricum, D. gmelinii, D. repens, D. sibirica subsp. arctica | D. alpina var. gracilescens |
Name authority | (Pallas) Thellung: Neue Denkschr. Schweiz. Naturf. Ges. 41: 318. (1907) | Elven & Al-Shehbaz: Novon 18: 326. (2008) |
Web links |