Draba globosa |
Draba verna |
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beavertip Draba, rockcress Draba, round-fruit Draba |
common Draba, common whitlow-grass, early witlow grass, nailwort, shadflower, spring Draba, spring whitlow-grass, spring whitlow-mustard, vernal whitlow grass, whitlow grass, whitlow wort |
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Habit | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Annuals; scapose. |
Stems | unbranched, 0.1–0.5 dm, glabrous. |
(few to many from base), unbranched, (0.2–)0.5–2(–3) dm, pubescent proximally, glabrous distally, trichomes simple and 2(–4)-rayed, 0.1–0.4 mm. |
Basal leaves | rosulate; sessile; blade (not fleshy), narrowly oblanceolate or lanceolate to linear, (0.2–)0.3–0.8 cm × 0.5–1.6(–2) mm, margins entire (ciliate, trichomes simple, 0.1–0.8 mm, apex acute, trichomes usually longer), surfaces glabrous, (midvein obscure abaxially). |
rosulate; petiolate; blade obovate, spatulate, oblanceolate, lanceolate, oblong, or, rarely, linear, 0.2–1.8(–3) cm × (0.5–)1–5(–10) mm, margins entire or 1–5-toothed on each side, surfaces pubescent with simple or stalked, 2–4-rayed trichomes, 0.1–0.5 mm. |
Cauline leaves | 0. |
0. |
Racemes | 2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
4–20(–30)-flowered, ebracteate, usually considerably elongated in fruit; rachis usually flexuous, glabrous. |
Flowers | sepals (persistent to near fruit maturity), ovate to broadly oblong, 2–3 mm, glabrous; petals white to pale yellow, obovate, 2.5–4 × 1.2–2 mm; anthers oblong, 0.4–0.6 mm. |
sepals (green or purplish), oblong, 1–2.5 mm, glabrescent or pubescent, (trichomes simple or 2-rayed); petals white, deeply 2-fid, (1.5–)2–4.5(–6) × 1–2 mm; anthers ovate, 0.2–0.4 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
divaricate to ascending, straight or slightly curved upward, (2–)5–20(–35) mm, glabrous. |
Fruits | ovate, plane, flattened, 4.5–8 × 2.5–4 mm; valves (distinctly veined), glabrous; ovules 8–16 per ovary; style (0.1–)0.2–0.6 mm. |
obovate, oblanceolate, lanceolate, elliptic, oblong, or linear, plane, flattened, (2.5–)4–9(–12) × 1.5–2.5(–3.5) mm; valves glabrous; ovules (20–)32–70(–84) per ovary; style 0.02–0.2 mm. |
Seeds | oblong, 1.1–1.4 × 0.8–1 mm. |
ovoid (slightly flattened), 0.3–0.6(–0.8) × 0.2–0.4 mm. |
2n | = 14, 16, 20, 24, 28, 30, 32, 34, 36, 38, 40, 52, 54, 58, 60, 64. |
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Draba globosa |
Draba verna |
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Phenology | Flowering Jun–Aug. | Flowering Feb–May. |
Habitat | Ridges, talus, alpine tundra and meadows | Cedar glades, lawns, fields, pastures, waste places, grassy hillsides, disturbed sites, roadsides |
Elevation | 2700-3900 m (8900-12800 ft) | 0-2500 m (0-8200 ft) |
Distribution |
ID; MT; UT; WY
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AL; AR; CA; CT; DC; DE; GA; IA; ID; IL; IN; KY; MA; MD; ME; MI; MO; MS; MT; NC; NH; NJ; NV; NY; OH; OR; PA; RI; SC; TN; UT; VA; VT; WA; WV; WY; AB; BC; NB; ON; QC; Europe; Asia; nw Africa [Introduced in North America; introduced also in Central America, South America, Australia]
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Discussion | Draba globosa is an apomictic species closely related to D. burkei (M. D. Windham, unpubl.). Though often treated as a variety of D. densifolia, it is morphologically and phyletically distinct from that species. Both R. C. Rollins (1993) and N. H. Holmgren (2005b) indicated that the species occurs in Colorado, but we have not seen material for that state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba verna represents a highly variable and taxonomically difficult complex within which species, subspecies, varieties, and forms have been named (O. E. Schulz 1927); only those synonyms pertaining to North America are listed above. Most of the taxonomic difficulties are the results of disploidy, autogamy, and hybridization. The morphological extremes are connected by intermediate forms in every conceivable character. Furthermore, there appears to be no correlation between morphology, cytology, geography, and ecology to support the division of this complex into meaningful taxa. A complex cytological picture was presented by Ø. Winge (1940), including the highest count of 2n = 94, which has not been confirmed by subsequent botanists. Erophila vulgaris de Candolle is an illegitimate name for Draba verna. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 308. | FNA vol. 7, p. 345. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. apiculata, D. densifolia var. apiculata, D. densifolia var. decipiens, D. densifolia var. globosa | D. boerhaavii, D. praecox, D. verna var. aestivalis, D. verna var. boerhaavii, Erophila boerhaavii, Erophila krockeri, Erophila praecox, Erophila verna, Erophila verna subsp. praecox |
Name authority | Payson: Amer. J. Bot. 4: 257. (1917) | Linnaeus: Sp. Pl. 2: 642. (1753) |
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