Draba standleyi |
Draba stenoloba |
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Standley's Draba |
Alaska Draba, Alaska whitlow-grass |
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Habit | Perennials; (densely pulvinate); caudex branched (with persistent, thickened petioles, branches compact); not scapose. | Biennials or perennials; (short-lived, not cespitose); caudex simple (not fleshy); scapose. |
Stems | unbranched, 0.3–1.3(–1.7) dm, usually glabrous throughout or sparsely pubescent proximally, rarely sparsely pubescent distally, trichomes simple and 2-rayed, 0.1–0.7 mm. |
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. |
Basal leaves | (not imbricate); rosulate; petiolate; petiole ciliate, (trichomes usually simple, rarely 2-rayed, not setiform); blade narrowly oblanceolate to linear-lanceolate, (strongly differentiated into blade and petiole), (1.2–)1.8–6(–8.5) cm × 1–5(–7) mm, margins entire or sparsely denticulate, (ciliate as petiole; midvein not prominent), surfaces glabrous or pubescent, usually with simple trichomes 0.1–0.8 mm, rarely 2-rayed. |
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. |
Cauline leaves | 1–8; sessile; blade lanceolate to narrowly oblong, margins usually entire, surfaces pubescent as basal. |
(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. |
Racemes | 5–17(–23)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely pubescent, trichomes simple and 2-rayed, (non-crisped). |
(2–)4–10(–15)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely sparsely pubescent. |
Flowers | sepals ovate, 2–2.5 mm, pubescent, (trichomes simple); petals yellow, oblanceolate, 4–6 × 1.5–2 mm; anthers oblong, 0.6–0.8 mm. |
(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. |
Fruiting pedicels | divaricate-ascending or ascending, straight, 3–9(–13) mm, usually glabrous, rarely sparsely pubescent, trichomes simple. |
horizontal to divaricate-ascending, straight, 3–14(–19) mm (subequaling or shorter than fruit), usually glabrous, rarely pubescent, trichomes 2–4-rayed. |
Fruits | linear-elliptic to elliptic, twisted or plane, flattened, 5–10(–13) × 1.5–2.5 mm; valves usually glabrous, rarely puberulent, trichomes simple, 0.05–0.1 mm; ovules 12–24 per ovary; style 0.7–1.4(–1.8) mm. |
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. |
Seeds | ovoid, 1–1.2 × 0.7–0.8 mm. |
ovoid, 0.9–1 × 0.5–0.6 mm. |
2n | = 40. |
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Draba standleyi |
Draba stenoloba |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Igneous rock outcrops, stabilized talus slopes | Grassy knolls, glacial moraines and creek banks, mesic meadows, alpine thickets |
Elevation | 1800-3100 m (5900-10200 ft) | 600-2300 m (2000-7500 ft) |
Distribution |
AZ; NM; TX |
AK; OR; WA; AB; BC; YT
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Discussion | Of conservation concern. Draba standleyi is a distinctive species that is sporadically distributed in the mountains of southwestern United States. It is known from the Chiricahua Mountains (Cochise County, southeastern Arizona), the Organ Mountains and Black Range (Dona Ana and Sierra counties, south-central New Mexico), and the Davis Mountains (Jeff Davis County, western Texas). It has not been reported from Mexico, though it is very likely to occur there. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 340. | FNA vol. 7, p. 340. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. gilgiana, D. chrysantha var. gilgiana | D. acinacis, D. hirta var. siliquosa, D. macouniana, D. nemorosa var. stenoloba, D. nitida var. praelonga, D. oligantha, D. stenoloba var. oligantha |
Name authority | J. F. Macbride & Payson: Ann. Missouri Bot. Gard. 5: 150. (1918) | Ledebour: Fl. Ross. 1: 154. (1841) |
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