Draba stenoloba |
Draba graminea |
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Alaska Draba, Alaska whitlow-grass |
Rocky Mountain Draba |
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Habit | Biennials or perennials; (short-lived, not cespitose); caudex simple (not fleshy); scapose. | Perennials; (cespitose); caudex simple or branched (with persistent leaf bases); not scapose. |
Stems | often unbranched, (0.2–)0.4–3(–3.4) dm, pubescent proximally, usually glabrous distally, rarely sparsely pubescent, trichomes short-stalked, 2–4-rayed, 0.1–0.4(–0.5) mm. |
unbranched, 0.1–0.5(–0.8) dm, usually pubescent throughout, rarely glabrous, trichomes simple or subsessile, 2-rayed or spurred, (crisped), 0.1–0.5 mm. |
Basal leaves | rosulate; petiole (obscure), margin ciliate, (trichomes simple, 0.2–0.4 mm); blade oblanceolate to obovate, 0.4–2.6(–3.1) cm × 1.5–7(–10) mm, margins entire or denticulate, (ciliate as petiole), surfaces pubescent, abaxially with short-stalked, 3- or 4-rayed trichomes, 0.1–0.5 mm, adaxially with simple and stalked, 2–4-rayed trichomes, 0.1–0.5 mm. |
rosulate; petiolate; petiole ciliate, (trichomes usually straight and simple, rarely also 2-rayed, 0.2–0.6(–0.8) mm); blade linear to linear-oblanceolate, (0.5–)1–4 cm × 0.3–2(–3) mm, margins entire (pubescent as petiole), surfaces glabrous. |
Cauline leaves | (0 or) 1 or 2 (3 or 4); sessile; blade elliptic to lanceolate or ovate, margins toothed, surfaces pubescent, abaxially with short-stalked 3- or 4-rayed trichomes, adaxially with simple and short-stalked, 2–4-rayed trichomes. |
(1–)3–9(–12) (as bracts); sessile; blade linear to oblanceolate or lanceolate, margins entire, (ciliate proximally, similar to basal). |
Racemes | (2–)4–10(–15)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely sparsely pubescent. |
3–15-flowered, bracteate, elongated in fruit; rachis not flexuous, usually pubescent as stem, rarely glabrous. |
Flowers | (chasmogamous, petaliferous); sepals (green or purplish), oblong, 1.5–2.5 mm, glabrous or pubescent, (trichomes simple); petals yellow, oblanceolate, 2.5–3.5 × 0.6–1 mm; anthers ovate, 0.25–0.4 mm. |
sepals ovate, 1.5–2.5 mm, glabrous or pubescent, (trichomes simple and short-stalked, 2-rayed); petals yellow, spatulate to obovate, 3–5 × 1.5–3 mm; anthers ovate, 0.3–0.5 mm. |
Fruiting pedicels | horizontal to divaricate-ascending, straight, 3–14(–19) mm (subequaling or shorter than fruit), usually glabrous, rarely pubescent, trichomes 2–4-rayed. |
divaricate-ascending, usually straight, rarely curved upward, 3–10(–15) mm, usually pubescent as stem, rarely glabrous. |
Fruits | linear or, rarely, linear-elliptic, plane, flattened, (8–)10–17(–20) × 1.5–2 mm; valves usually glabrous, rarely sparsely puberulent, trichomes simple; ovules 24–36 per ovary; style 0.01–0.15 mm. |
ovate-elliptic to lanceolate, slightly twisted or plane, flattened, 5–11 × 2.5–5 mm; valves glabrous; ovules 8–16 per ovary; style 0.2–0.7 mm. |
Seeds | ovoid, 0.9–1 × 0.5–0.6 mm. |
ovoid, 1.2–1.5 × 0.7–1 mm. |
2n | = 40. |
= 18. |
Draba stenoloba |
Draba graminea |
|
Phenology | Flowering Jun–Jul. | Flowering Jul–Sep. |
Habitat | Grassy knolls, glacial moraines and creek banks, mesic meadows, alpine thickets | Rocky areas and ridges, alpine tundra, gravel bars in streams |
Elevation | 600-2300 m (2000-7500 ft) | 3000-4100 m (9800-13500 ft) |
Distribution |
AK; OR; WA; AB; BC; YT
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CO
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Discussion | Draba stenoloba is occasionally confused with D. albertina, but is easily recognized by having exclusively 2–4-rayed (versus mostly simple) trichomes on stems proximally. It is rarely encountered and apparently confined to the Pacific Northwest. In contrast, D. albertina is common and widespread in the mountains of western North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Draba graminea is occasionally confused with D. crassa, which occupies similar habitats and elevations. It is easily distinguished from the latter by having narrower [0.3–2(–3) versus 2.5–8(–10) mm wide] basal leaves and bracteate (versus ebracteate) racemes. It is known to us only from Hinsdale, La Plata, Ouray, San Juan, and San Miguel counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 340. | FNA vol. 7, p. 309. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. acinacis, D. hirta var. siliquosa, D. macouniana, D. nemorosa var. stenoloba, D. nitida var. praelonga, D. oligantha, D. stenoloba var. oligantha | Braya graminea, D. chrysantha var. graminea, D. chrysantha var. hirticaulis |
Name authority | Ledebour: Fl. Ross. 1: 154. (1841) | Greene: Pl. Baker. 3: 5. (1901) |
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