Draba breweri |
Draba aleutica |
|
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Brewer's whitlow grass, cushion Draba |
Aleutian Draba |
|
Habit | Perennials; (cespitose, grayish pubescent); caudex branched (sometimes covered with persistent leaf bases, branches short, compact); sometimes scapose. | Perennials; (densely matted); caudex branched (with persistent leaf remains, some branches terminating in sterile rosettes); scapose. |
Stems | unbranched, (0.1–)0.2–1(–1.5) dm, pubescent throughout, trichomes stalked, 4–10-rayed, 0.1–0.3 mm. |
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; petiolate; petiole base ciliate, margin not ciliate, (trichomes simple and 2-rayed, 0.3–0.8 mm); blade oblanceolate to obovate, (0.3–)0.4–1.5(–2.5) cm × 1.5–3(–5) mm, margins usually entire, rarely dentate, surfaces densely pubescent with stalked, 4–10-rayed, stellate trichomes, 0.1–0.2 mm (sometimes 1 or more rays spurred). |
(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 | 0–3(–6); sessile; blade oblong or lanceolate to ovate, margins entire (sometimes ciliate at base), surfaces usually pubescent as basal. |
0. |
Racemes | (5–)7–18(–24)-flowered, ebracteate, slightly to considerably elongated in fruit; rachis not flexuous, pubescent with stalked, 4–10-rayed trichomes, (0.1–0.3 mm). |
(1 or) 2–5(–9)-flowered, ebracteate, not or slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals (persistent), ovate, 1.2–2 mm, pubescent, (trichomes short-stalked, 2–6-rayed); petals white, spatulate to oblanceolate, 2–3 × 0.7–1.1 mm; anthers ovate, 0.2–0.25 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 | ascending, (sometimes slightly appressed to rachis), straight, 1.5–3(–4) mm, pubescent as rachis. |
divaricate, straight, 1.5–4(–6) mm, pubescent, trichomes simple with fewer, 2-rayed, stalked ones. |
Fruits | lanceolate or oblong to linear, usually slightly to strongly twisted, rarely plane, flattened, 3.5–9(–11) × 1.5–2.5 mm; valves pubescent, trichomes short-stalked, 2–5-rayed, 0.05–0.25 mm; ovules 28–40 per ovary; style 0.1–0.3(–0.4) 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 | ovoid, 0.5–0.7 × 0.3–0.5 mm. |
oblong, (slightly flattened), 1.4–1.8 × 0.9–1.1 mm. |
2n | = 32. |
|
Draba breweri |
Draba aleutica |
|
Phenology | Flowering Jul–Aug. | Flowering May–Jul. |
Habitat | Rock outcrops, talus, exposed ridges, alpine areas | Gravelly soil, retreating snow banks, fellfields |
Elevation | 3100-4100 m (10200-13500 ft) | 200-400 m (700-1300 ft) |
Distribution |
CA
|
AK; e Asia (Russian Far East) |
Discussion | The circumscription of Draba breweri was expanded by R. C. Rollins (1993) to include D. cana. Plants of D. cana differ from those of D. breweri by being non-cespitose (versus cespitose) and taller [(4–)10–30(–38) versus (1–)2–9(–15) cm], and by having basally bracteate (versus ebracteate) racemes, and stems, pedicels, and sepals pubescent with a mixture of simple and branched (versus exclusively branched) trichomes. Draba breweri is known to us from Alpine, Fresno, Inyo, Mono, Plumas, Tulare, and Tuolumne counties. (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. 297. | FNA vol. 7, p. 289. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. breweri var. sublaxa | D. behringii |
Name authority | S. Watson: Proc. Amer. Acad. Arts 23: 260. (1888) | Ekman: Svensk Bot. Tidskr. 30: 522, figs. 3c,d. (1936) |
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