Draba paucifructa |
Draba verna |
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Charleston Mountain 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; caudex simple or branched (not fleshy, usually with some persistent leaf remains); sometimes scapose. | Annuals; scapose. |
Stems | unbranched, (0.1–)0.3–0.9 dm, glabrous throughout or sparsely pubescent proximally, trichomes simple and 2–6-rayed, 0.1–0.5 mm. |
(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; petiolate; petiole (0–0.5 cm), ciliate throughout; blade oblanceolate to obovate, 0.4–1.7(–2.3) cm × 1.6–4(–6) mm, margins usually entire, rarely denticulate, (sparsely ciliate, trichomes simple, 0.3–0.8 mm), surfaces pubescent, abaxially with stalked, (2–)4(–6)-rayed trichomes, (0.05–)0.1–0.6 mm, adaxially with simple and fewer, stalked, 2–4-rayed ones. |
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 or 1; sessile; blade ovate to lanceolate, margins entire, surfaces pubescent as basal. |
0. |
Racemes | (2–)4–9(–12)-flowered, ebracteate, elongated in fruit; rachis slightly flexuous, glabrous. |
4–20(–30)-flowered, ebracteate, usually considerably elongated in fruit; rachis usually flexuous, glabrous. |
Flowers | sepals ovate, 1.2–1.7 mm, pubescent, (trichomes simple and short-stalked, 2- or 3-rayed); petals yellowish (quickly fading white), spatulate, 1.8–2.2 × 0.6–1 mm; anthers ovate, 0.25–0.3 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, 2–5(–8) mm, glabrous. |
divaricate to ascending, straight or slightly curved upward, (2–)5–20(–35) mm, glabrous. |
Fruits | elliptic to linear lanceolate, plane, flattened, 5–10(–12) × 1.7–2(–2.5) mm; valves glabrous; ovules 20–30 per ovary; style 0.08–0.2 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, 0.9–1.2 × 0.5–0.8 mm. |
ovoid (slightly flattened), 0.3–0.6(–0.8) × 0.2–0.4 mm. |
2n | = 40. |
= 14, 16, 20, 24, 28, 30, 32, 34, 36, 38, 40, 52, 54, 58, 60, 64. |
Draba paucifructa |
Draba verna |
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Phenology | Flowering Jun–Jul. | Flowering Feb–May. |
Habitat | Moist, shaded slopes among limestone and dolomite rocks | Cedar glades, lawns, fields, pastures, waste places, grassy hillsides, disturbed sites, roadsides |
Elevation | 2600-3500 m (8500-11500 ft) | 0-2500 m (0-8200 ft) |
Distribution |
NV |
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 | Of conservation concern. Draba paucifructa is known from the Charleston Mountains in Clark County. M. D. Windham (2004) suggested that it is an allopolyploid resulting from hybridization between D. albertina and D. lonchocarpa, and he discussed the morphological features that distinguish this species from its putative parents. (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. 327. | FNA vol. 7, p. 345. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | 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 | Clokey & C. L. Hitchcock: Madroño 5: 127. (1939) | Linnaeus: Sp. Pl. 2: 642. (1753) |
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