Draba sibirica |
Draba pennellii |
|
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Siberian whitlowgrass |
schell creek Draba |
|
Habit | Perennials; (stoloniferous); caudex branched (sparsely covered with persistent petiole remains, branches slender, creeping); scapose. | Perennials; (cespitose, often forming mats); caudex branched (elongated, with persistent leaf bases, branches sometimes terminating in sterile rosettes); sometimes 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–)0.3–0.7(–1) dm, pubescent proximally, trichomes simple and spurred, 0.4–0.8 mm, and short-stalked, 2–4-rayed, 0.1–0.4 mm, (sometimes with simple trichomes distally). |
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). |
subrosulate; sessile; blade oblanceolate to oblong, (0.3–)0.5–0.8 cm × 1–3 mm, (base ciliate, trichomes simple, 0.2–0.8 mm), margins entire, (not ciliate), surfaces usually pubescent, with stalked, (2–)4 (or 5)-rayed trichomes, 0.2–0.5 mm, adaxially sometimes glabrate, or primarily with simple trichomes, 0.3–0.8 mm. |
Cauline leaves | 0. |
(0 or) 1–4; sessile; blade ovate to oblong, margins entire, surfaces pubescent as basal. |
Racemes | 7–20-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous (straight), glabrous. |
(3–)7–15(–20)-flowered, ebracteate, elongated in fruit; rachis not flexuous, 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 ovate to oblong, 2–3 mm, pubescent, (trichomes simple, with fewer, short-stalked, 2-rayed ones); petals white, obovate, 3.5–6 × 1.5–2.8 mm; anthers oblong, 0.5–0.6 mm. |
Fruiting pedicels | divaricate, straight or curved, (often filiform), 5–18(–23) mm, glabrous. |
divaricate-ascending to ascending, straight, 3–10 mm, pubescent, trichomes simple and short-stalked, 2–4-rayed, (0.1–0.4 mm). |
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. |
broadly or, rarely, narrowly lanceolate to elliptic or ovate, plane or slightly twisted, flattened, (4)5–8(–10) × 2–3.2 mm; valves (each with distinct midvein), pubescent, trichomes simple and short-stalked, 2-rayed, 0.08–0.2 mm; ovules 12–24 per ovary; style (0.7–)1–1.8(–2.1) mm. |
Seeds | (brown), ovoid, 0.9–1.2 × 0.5–0.6 mm. |
oblong, 0.9–1.3 × 0.7–1 mm. |
2n | = 16. |
= 32. |
Draba sibirica |
Draba pennellii |
|
Phenology | Flowering May–Jul. | Flowering May–Jul. |
Habitat | Wet places on rocky slopes | Rock outcrops and talus slopes in pinyon-juniper, sagebrush, mountain shrub, and mixed conifer communities |
Elevation | 0-300 m (0-1000 ft) | 1900-3500 m (6200-11500 ft) |
Distribution |
Greenland; Europe (Russia); Asia (Caucasus, Iran, Russian Far East, Siberia, Turkey, central republics) |
NV |
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.) |
Of conservation concern. Draba pennellii is known from White Pine County in east-central Nevada. It is easily distinguished from other white-flowered species in the region by its elongated, many-branched caudices, long styles, usually few-leaved or, rarely, leafless flowering stems, and distinct midvein on fruit valves. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 337. | FNA vol. 7, p. 329. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Lepidium sibiricum, D. gmelinii, D. repens, D. sibirica subsp. arctica | |
Name authority | (Pallas) Thellung: Neue Denkschr. Schweiz. Naturf. Ges. 41: 318. (1907) | Rollins: J. Arnold Arbor. 64: 502. (1983) |
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