Draba sibirica |
Draba aureola |
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Siberian whitlowgrass |
alpine whitlow-grass, golden alpine Draba, golden Draba, great alpine whitlow-grass, Mt. Lassen Draba, Mt. Lassen Draba whitlow-grass, Mt. Lassen whitlow-grass |
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Habit | Perennials; (stoloniferous); caudex branched (sparsely covered with persistent petiole remains, branches slender, creeping); scapose. | Perennials; (short-lived); caudex simple or branched (poorly developed, with persistent dry leaves); not 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 or branched, 0.3–1.5 dm, hirsute throughout, trichomes simple and long-stalked, 2–4-rayed, 0.2–1.5 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). |
(forming dense clusters); rosulate; sessile; blade oblanceolate to linear, (0.7–)1–2.5(–3.2) cm × 2–3.5(–5) mm, margins entire, (ciliate, trichomes simple and 2-rayed, 0.5–1.5 mm), surfaces densely hirsute, abaxially with stalked, 3–5-rayed trichomes, 0.1–0.5 mm, adaxially with simple and long-stalked, 2-rayed trichomes, to 1 mm, with smaller, 3–5-rayed ones. |
Cauline leaves | 0. |
5–33; sessile; blade oblong to linear, margins entire, surfaces pubescent as basal. |
Racemes | 7–20-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous (straight), glabrous. |
12–83-flowered, ebracteate or proximalmost 1–9 flowers bracteate, slightly or not elongated in fruit; rachis not flexuous, hirsute 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 ovate, 2.5–4 mm, glabrous; petals bright yellow, linear to linear-oblanceolate, 4–6 × 0.5–1(–1.2) mm; anthers narrowly oblong, 0.8–1 mm. |
Fruiting pedicels | divaricate, straight or curved, (often filiform), 5–18(–23) mm, glabrous. |
horizontal to divaricate, usually straight, rarely curved upward, (3–)5–12(–19) mm, hirsute 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. |
oblong or, rarely, oblong-ovate, plane, flattened, (6–)9–14(–16) × 3–5 mm; valves pubescent, trichomes stalked, 2–4-rayed, 0.07–0.5 mm; ovules 10–20 per ovary; style (0.6–)1–1.6(–2) mm. |
Seeds | (brown), ovoid, 0.9–1.2 × 0.5–0.6 mm. |
oblong, 1.4–1.9 × 0.8–1.1 mm. |
2n | = 16. |
= 20. |
Draba sibirica |
Draba aureola |
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Phenology | Flowering May–Jul. | Flowering Jul–Aug. |
Habitat | Wet places on rocky slopes | Open conifer forests, alpine meadows and moraines, talus slopes |
Elevation | 0-300 m (0-1000 ft) | 2200-3200 m (7200-10500 ft) |
Distribution |
Greenland; Europe (Russia); Asia (Caucasus, Iran, Russian Far East, Siberia, Turkey, central republics) |
CA; OR; WA
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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.) |
Draba aureola is known from Lassen, Shasta, and Siskiyou counties in California, Deschutes County in Oregon, and Lewis and Pierce counties in Washington. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 337. | FNA vol. 7, p. 295. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lepidium sibiricum, D. gmelinii, D. repens, D. sibirica subsp. arctica | D. aureola var. paniculata |
Name authority | (Pallas) Thellung: Neue Denkschr. Schweiz. Naturf. Ges. 41: 318. (1907) | S. Watson: in W. H. Brewer et al., Bot. California 2: 430. (1880) |
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