Draba cana |
Draba grandis |
|
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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 |
north Pacific Draba |
|
Habit | Perennials; caudex simple or branched (branches short); not scapose. | Perennials; caudex simple or branched (fleshy, with persistent leaf bases); not scapose. |
Stems | 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). |
(decumbent), unbranched, (0.2–)0.5–2.7(–3.7) dm, pubescent throughout, trichomes 2–4-rayed, 0.05–0.2 mm. |
Basal leaves | 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. |
rosulate; long-petiolate; petiole (winged, (1–)4–15 cm), often not ciliate (or ciliate to blade apex, trichomes simple, 0.3–0.8 mm); blade (somewhat fleshy), oblanceolate to spatulate or obovate, (1–)2–11(–17) cm × (5–)8–30(–45) mm, margins often coarsely dentate, (pubescent as petiole), surfaces usually pubescent, abaxially with stalked, 2–4-rayed trichomes, 0.05–0.25 mm, adaxially similar, or also with simple and long-stalked, 2-rayed trichomes, to 0.8 mm, rarely glabrescent, with mostly simple and 2-rayed trichomes. |
Cauline leaves | 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). |
2–12(–16); sessile or petiolate; blade oblanceolate to obovate, margins dentate or entire, surfaces pubescent as basal. |
Racemes | (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. |
5–26(–32)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | 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. |
sepals broadly ovate, 3–4 mm, pubescent, (trichomes simple and short-stalked, 2-rayed); petals yellow, oblanceolate to spatulate, 4.5–7 × 1.8–3 mm; anthers oblong, 0.7–1 mm. |
Fruiting pedicels | suberect or ascending, straight, 2–5(–10) mm, pubescent as rachis. |
horizontal to divaricate-ascending or ascending, usually straight, rarely curved upward, (5–)10–22(–27) mm, pubescent, trichomes 2–4-rayed (0.05–0.3 mm), sometimes with simple and spurred ones. |
Fruits | (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. |
oblong to lanceolate, or ovate to suborbicular, slightly twisted or plane, flattened, (6–)10–20(–25) × 4–7(–9) mm; valves glabrous; ovules 24–52 per ovary; style (0.2–)0.4–1.6(–2) mm. |
Seeds | ovoid, 0.5–0.7(–0.9) × 0.3–0.5 mm. |
ovoid, 1.4–2 × 0.8–1.2 mm. |
2n | = 32. |
= 36. |
Draba cana |
Draba grandis |
|
Phenology | Flowering (May-)Jun–Aug. | Flowering May–Jul. |
Habitat | Rock outcrops and talus, open prairie benchlands, roadsides, meadows, alpine tundra | Rocky bluffs above salt-water beaches, loamy seaside banks, sea bird rookeries, coastal herbaceous tundra and sandy blowouts |
Elevation | 0-4100 m (0-13500 ft) | 0-50(-200) m (0-200(-700) ft) |
Distribution |
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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AK; BC; e Asia (Kuril and Ratmanov islands, Russian Far East) |
Discussion | 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.) |
Almost all recent North American authors have used the name Draba hyperborea for this species. A. N. Berkutenko (1995) clearly showed that the type of that name belongs to an entirely different species that she placed in the genus Schivereckia Andrzejowski ex de Candolle. Draba grandis thus becomes the correct name for the North American taxon. Except for its fleshy leaves, Nesodraba is indistinguishable morphologically and molecularly from other species of Draba. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 298. | FNA vol. 7, p. 309. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. breweri var. cana, D. valida | Cochlearia siliquosa, Cochlearia spathulata, D. greenei, D. hatchiae, D. hyperborea var. spathulata, D. spathulata, Nesodraba grandis, Nesodraba megalocarpa, Nesodraba siliquosa |
Name authority | Rydberg: Bull. Torrey Bot. Club 29: 241. (1902) | Langsdorff ex de Candolle: Syst. Nat. 2: 355. (1821) |
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