Draba stenoloba |
Draba ogilviensis |
|
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Alaska Draba, Alaska whitlow-grass |
Ogilvie Range Draba |
|
Habit | Biennials or perennials; (short-lived, not cespitose); caudex simple (not fleshy); scapose. | Perennials; (stoloniferous); caudex branched (sparsely covered with petiole remains, branches slender, creeping, loosely matted); often 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, 0.4–1.5 dm, glabrous or pubescent throughout, trichomes simple and short-stalked, 2- or 3-rayed, 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. |
not rosulate; (subopposite); petiolate; petiole base and margin ciliate or not, (trichomes simple, 0.2–0.8 mm); blade oblanceolate or lanceolate, 0.5–1.5 cm × 1.5–5 mm, margins entire, surfaces glabrous or sparsely pubescent with simple and stalked, 2–4-rayed trichomes, 0.1–0.5 mm, (midvein obscure abaxially). |
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. |
(0 or) 1 or 2; (subopposite); sessile; blade ovate or oblong, margins entire, surfaces pubescent as basal. |
Racemes | (2–)4–10(–15)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely sparsely pubescent. |
5–13-flowered, ebracteate, elongated in fruit; rachis not or slightly flexuous, glabrous or pubescent as stem. |
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, 2–3 mm, glabrous or pubescent, (trichomes simple); petals golden yellow, obovate, 3.5–6 × 2–3 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. |
horizontal to divaricate, often curved upward, 6–13(–17) mm, glabrous or sparsely pubescent, trichomes simple and 2-rayed. |
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. |
oblong, plane, flattened, 6–9 × 2–3 mm; valves glabrous; ovules 8–20 per ovary; style 0.4–1 mm. |
Seeds | ovoid, 0.9–1 × 0.5–0.6 mm. |
ovoid, 0.9–1 × ca. 0.6 mm. |
2n | = 40. |
= 16. |
Draba stenoloba |
Draba ogilviensis |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Aug. |
Habitat | Grassy knolls, glacial moraines and creek banks, mesic meadows, alpine thickets | Tundra, river flats and banks, exposed talus slopes, hummocks in wet sedge meadows |
Elevation | 600-2300 m (2000-7500 ft) | 900-2200 m (3000-7200 ft) |
Distribution |
AK; OR; WA; AB; BC; YT
|
AK; NT; YT |
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.) |
The limits of Draba ogilviensis were confused by authors who reduced it to synonymy of D. juvenilis or D. sibirica. A thorough discussion of the three species and their distinguishing characteristics was provided by D. F. Murray and C. L. Parker (1999). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 340. | FNA vol. 7, p. 324. |
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 | |
Name authority | Ledebour: Fl. Ross. 1: 154. (1841) | Hultén: Bot. Not. 119: 315, fig. 2. (1966) |
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