Draba heilii |
Draba cana |
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Brewer's Draba, canescent Draba, canescent whitlow-mustard, cushion Draba, hoary Draba, hoary whitlow-grass, lance-leaf Draba, lance-leaf whitlow-grass |
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Habit | Perennials; (densely cespitose); caudex few-branched (compact, with persistent, thickened leaves); not scapose. | Perennials; caudex simple or branched (branches short); not 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. |
unbranched or branched distally, (0.6–)1–3(–3.8) dm, pubescent throughout, trichomes simple, 0.5–1mm, with 4–10-rayed ones, 0.05–0.2 mm (mostly branched on basal parts). |
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; petiolate; petiole ciliate throughout; blade linear to oblanceolate or oblong, (0.5–)0.8–2(–3.5) cm × 1.5–4(–11) mm, margins entire or dentate, (base and apex ciliate, trichomes simple, 0.3–0.8 mm), surfaces pubescent with short-stalked, 4–12-rayed trichomes, 0.1–0.3 mm. |
Cauline leaves | 6–8; sessile; blade linear-oblong, 0.5–0.8 cm × 1–2 mm (widest about base), margins entire, (ciliate). |
3–10(–17), (not overlapping); sessile; blade lanceolate to ovate or oblong, margins entire or dentate, surfaces pubescent as basal (adaxially with simple and forked trichomes near blade base). |
Racemes | 10–26-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely pubescent, (trichomes non-crisped, simple and 2-rayed). |
(10–)15–47(–63)-flowered, basally bracteate, often considerably elongated in fruit; rachis not flexuous, densely pubescent, trichomes 4–10-rayed (0.05–0.2 mm), and fewer simple ones. |
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. |
sepals (green or lavender), oblong to ovate, 1.5–2 mm, pubescent, (trichomes simple and few-rayed); petals white, oblanceolate to spatulate, 2.3–3.7(–4.5) × 0.7–1.7 mm; anthers ovate, 0.1–0.2 mm. |
Fruiting pedicels | ascending, straight, 3–5(–7) mm, usually glabrous, rarely pilose, (trichomes simple and 2-rayed, stalked). |
suberect or ascending, straight, 2–5(–10) mm, pubescent as rachis. |
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. |
(subappressed to rachis), linear-lanceolate to linear or, rarely, ovate-oblong, slightly twisted or plane, flattened, (5–)6–11 × 1.5–2(–2.5) mm; valves pubescent, trichomes short-stalked, 3–7-rayed, 0.05–0.3 mm; ovules 28–48 per ovary; style 0.1–0.6 mm. |
Seeds | ovoid, 1 × 0.6 mm. |
ovoid, 0.5–0.7(–0.9) × 0.3–0.5 mm. |
2n | = 32. |
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Draba heilii |
Draba cana |
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Phenology | Flowering Jun–Jul. | Flowering (May-)Jun–Aug. |
Habitat | Alpine tundra | Rock outcrops and talus, open prairie benchlands, roadsides, meadows, alpine tundra |
Elevation | ca. 3700 m (ca. 12100 ft) | 0-4100 m (0-13500 ft) |
Distribution |
NM |
AK; CA; CO; ID; ME; MI; MT; NH; NM; NV; SD; UT; VT; WA; WI; WY; AB; BC; MB; NB; NF; NT; ON; QC; SK; YT; Greenland
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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.) |
The limits of Draba cana have long been confused, and the species was treated as a synonym of the Himalayan D. lanceolata Royle (M. L. Fernald 1934; C. L. Hitchcock 1941) or as a variety of the western North American D. breweri (R. C. Rollins 1993). However, G. A. Mulligan (1971) clearly demonstrated that all three are distinct and should be maintained. Some Utah plants corresponding to the type of D. valida have shorter and wider oblong-ovate fruits. In all other aspects, they are indistinguishable from D. cana. Additional studies are needed to establish whether such plants should be formally recognized. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 311. | FNA vol. 7, p. 298. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. breweri var. cana, D. valida | |
Name authority | Al-Shehbaz: Harvard Pap. Bot. 14: 83, fig. 1. (2009) | Rydberg: Bull. Torrey Bot. Club 29: 241. (1902) |
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