Draba globosa |
Draba aleutica |
|
---|---|---|
beavertip Draba, rockcress Draba, round-fruit Draba |
Aleutian Draba |
|
Habit | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (densely matted); caudex branched (with persistent leaf remains, some branches terminating in sterile rosettes); scapose. |
Stems | unbranched, 0.1–0.5 dm, glabrous. |
unbranched, 0.04–0.4 dm, usually pubescent throughout, sometimes glabrous basally, trichomes simple, 0.1–1 mm, with 2-rayed ones. |
Basal leaves | rosulate; sessile; blade (not fleshy), narrowly oblanceolate or lanceolate to linear, (0.2–)0.3–0.8 cm × 0.5–1.6(–2) mm, margins entire (ciliate, trichomes simple, 0.1–0.8 mm, apex acute, trichomes usually longer), surfaces glabrous, (midvein obscure abaxially). |
(densely imbricate); rosulate; petiolate; petiole base and margin ciliate, (trichomes simple, to 1.4 mm); blade oblanceolate to spatulate or obovate, 0.4–0.8(–1) cm × 2–3.5(–4.5) mm, margins entire, surfaces usually sparsely to densely pilose with simple trichomes, to 1.4 mm, with much fewer, stalked, 2-rayed ones, (sometimes surfaces glabrous, or adaxially only, midvein obscure abaxially). |
Cauline leaves | 0. |
0. |
Racemes | 2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
(1 or) 2–5(–9)-flowered, ebracteate, not or slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals (persistent to near fruit maturity), ovate to broadly oblong, 2–3 mm, glabrous; petals white to pale yellow, obovate, 2.5–4 × 1.2–2 mm; anthers oblong, 0.4–0.6 mm. |
sepals oblong, 2–3 mm, glabrous or sparsely pubescent, (trichomes simple); petals yellowish green to pale yellow, linear-oblanceolate, 3–4 × 0.5–0.8 mm; anthers oblong, 0.4–0.5 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
divaricate, straight, 1.5–4(–6) mm, pubescent, trichomes simple with fewer, 2-rayed, stalked ones. |
Fruits | ovate, plane, flattened, 4.5–8 × 2.5–4 mm; valves (distinctly veined), glabrous; ovules 8–16 per ovary; style (0.1–)0.2–0.6 mm. |
broadly obovoid to subglobose, plane, slightly flattened, 3–5 × 3–4.5 mm; valves glabrous or pubescent, trichomes simple, 0.1–0.3 mm; ovules 4–8 per ovary; style 0.1–0.4 mm. |
Seeds | oblong, 1.1–1.4 × 0.8–1 mm. |
oblong, (slightly flattened), 1.4–1.8 × 0.9–1.1 mm. |
Draba globosa |
Draba aleutica |
|
Phenology | Flowering Jun–Aug. | Flowering May–Jul. |
Habitat | Ridges, talus, alpine tundra and meadows | Gravelly soil, retreating snow banks, fellfields |
Elevation | 2700-3900 m (8900-12800 ft) | 200-400 m (700-1300 ft) |
Distribution |
ID; MT; UT; WY
|
AK; e Asia (Russian Far East) |
Discussion | Draba globosa is an apomictic species closely related to D. burkei (M. D. Windham, unpubl.). Though often treated as a variety of D. densifolia, it is morphologically and phyletically distinct from that species. Both R. C. Rollins (1993) and N. H. Holmgren (2005b) indicated that the species occurs in Colorado, but we have not seen material for that state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Draba aleutica is known in the flora area from the Aleutian Islands (e.g., Atka, Attu) and on the Pribilov Islands (St. Paul), as well as in the Alaskan Peninsula near Ugashik. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 308. | FNA vol. 7, p. 289. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. apiculata, D. densifolia var. apiculata, D. densifolia var. decipiens, D. densifolia var. globosa | D. behringii |
Name authority | Payson: Amer. J. Bot. 4: 257. (1917) | Ekman: Svensk Bot. Tidskr. 30: 522, figs. 3c,d. (1936) |
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