Draba heilii |
Draba stenoloba |
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Alaska Draba, Alaska whitlow-grass |
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Habit | Perennials; (densely cespitose); caudex few-branched (compact, with persistent, thickened leaves); not scapose. | Biennials or perennials; (short-lived, not cespitose); caudex simple (not fleshy); scapose. |
Stems | unbranched or branched distally, 0.3–0.7 dm, glabrous throughout or, rarely, pilose, trichomes simple and stalked, 2-rayed, 0.2–0.5 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 | (persistent, imbricate); rosulate; undifferentiated into blade and petiole (becoming indurate at base); blade linear-lanceolate, 0.5–0.8 cm × 1–1.5(–2) mm, margins entire, surfaces glabrous or, rarely, pilose with simple and stalked, 2-rayed trichomes, (margins ciliate with simple and, rarely, 2-rayed setiform trichomes, 0.5–1.3 mm, midvein prominent). |
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 | 6–8; sessile; blade linear-oblong, 0.5–0.8 cm × 1–2 mm (widest about base), margins entire, (ciliate). |
(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 | 10–26-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely pubescent, (trichomes non-crisped, simple and 2-rayed). |
(2–)4–10(–15)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely sparsely pubescent. |
Flowers | sepals ovate, 1.7–2.7 mm, usually glabrous, rarely pilose, (trichomes simple); petals yellow, oblong-oblanceolate, 4–6 × 1.5–2 mm; anthers oblong, 0.5–0.6 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 | ascending, straight, 3–5(–7) mm, usually glabrous, rarely pilose, (trichomes simple and 2-rayed, stalked). |
horizontal to divaricate-ascending, straight, 3–14(–19) mm (subequaling or shorter than fruit), usually glabrous, rarely pubescent, trichomes 2–4-rayed. |
Fruits | narrowly lanceolate, twisted 1/2 turn or plane, flattened, 7–10 × 1.3–1.6 mm; valves glabrous; ovules 16–20 per ovary; style 0.7–1.3 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 × 0.6 mm. |
ovoid, 0.9–1 × 0.5–0.6 mm. |
2n | = 40. |
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Draba heilii |
Draba stenoloba |
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Phenology | Flowering Jun–Jul. | Flowering Jun–Jul. |
Habitat | Alpine tundra | Grassy knolls, glacial moraines and creek banks, mesic meadows, alpine thickets |
Elevation | ca. 3700 m (ca. 12100 ft) | 600-2300 m (2000-7500 ft) |
Distribution |
NM |
AK; OR; WA; AB; BC; YT
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Discussion | Draba heilii is restricted to Mora and Rio Arriba counties. (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. 311. | FNA vol. 7, p. 340. |
Parent taxa | ||
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 | Al-Shehbaz: Harvard Pap. Bot. 14: 83, fig. 1. (2009) | Ledebour: Fl. Ross. 1: 154. (1841) |
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