Draba globosa |
Draba fladnizensis |
|
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beavertip Draba, rockcress Draba, round-fruit Draba |
arctic Draba, Austrian Draba, Austrian whitlow-grass |
|
Habit | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (sometimes cespitose); caudex simple or branched (with persistent leaf bases); usually scapose. |
Stems | unbranched, 0.1–0.5 dm, glabrous. |
unbranched, (0.2–)0.3–1(–1.3) dm, glabrous. |
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; petiole (obscure), margin ciliate, (trichomes simple or 2-rayed, 0.25–0.6 mm); blade linear to oblanceolate or narrowly obovate, (0.3–)0.4–1.2(–1.6) cm × 1–3(–4) mm, margins usually entire, rarely toothed, surfaces abaxially pubescent or glabrous, trichomes simple, sometimes with fewer, short-stalked, 2-rayed ones, (midvein prominent), adaxially often glabrous. |
Cauline leaves | 0. |
0–2; sessile; blade oblong to ovate, margins entire, (ciliate). |
Racemes | 2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
(2 or) 3–11(–14)-flowered, usually ebracteate, rarely proximalmost flowers bracteate, elongated in fruit; rachis not 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), ovate, 1.2–2.2 mm, glabrous or pubescent, (trichomes simple); petals white, spatulate, 2–2.5 × 0.8–1.5 mm; anthers ovate, 0.2–0.25 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
divaricate-ascending, often straight, (1–)2–5(–6) 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. |
elliptic-lanceolate to oblong, plane, flattened, 3–8(–9) × 1.5–2 mm; valves glabrous; ovules 12–24 per ovary; style 0.05–0.2(–0.3) mm. |
Seeds | oblong, 1.1–1.4 × 0.8–1 mm. |
oblong to elliptic, 0.8–1 × 0.5–0.6 mm. |
2n | = 16. |
|
Draba globosa |
Draba fladnizensis |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Ridges, talus, alpine tundra and meadows | Rock outcrops and talus, alpine meadows, sandy gravel |
Elevation | 2700-3900 m (8900-12800 ft) | 0-1400 m at higher latitudes, 3000-3800 m at lower latitudes (0-4600 ft at higher latitudes, 9800-12500 ft at lower latitudes) |
Distribution |
ID; MT; UT; WY
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AK; CO; UT; WY; BC; NT; NU; QC; YT; Greenland; c Europe; s Europe; Asia; circumpolar and high alpine areas
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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.) |
Rollins reduced Draba pattersonii to a variety of D. fladnizensis and separated the two primarily on plant size and minor differences in fruit shape. Examination of D. fladnizensis specimens collected throughout Europe and North America reveals that the alleged differences between the two taxa are artificial. The type material of D. pattersonii, which was collected in Colorado, is a mixture of plants highly variable in their type of indumentum. The specimens have no flowers, but the habit, fruits, and leaves are nearly indistinguishable from those of D. fladnizensis from higher latitudes. In the absence of flowers, the white-flowered Draba fladnizensis (2n = 16) is often confused with the yellow-flowered D. crassifolia (2n = 40). The latter is an annual or short-lived perennial that rarely forms a well-developed caudex, whereas D. fladnizensis almost always produces a distinct caudex. Although most individuals of both species are scapose, they occasionally produce one or two cauline leaves. The cauline leaves are usually glabrous in D. crassifolia and ciliate in D. fladnizensis; in the latter, the distalmost cauline leaf usually subtends the proximalmost flower. Finally, the seeds in D. fladnizensis are slightly larger (0.8–0.1 × 0.5–0.6 versus 0.7–0.8 × 0.4–0.5 mm) than those of D. crassifolia, though the reliability of this distinction needs to be examined in greater detail. N. H. Holmgren (2005b) reported D. fladnizensis from central Nevada, but we have not seen any material of the species from that state. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 308. | FNA vol. 7, p. 307. |
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. fladnizensis var. pattersonii, D. pattersonii, D. pattersonii var. hirticaulis, D. wahlenbergii |
Name authority | Payson: Amer. J. Bot. 4: 257. (1917) | Wulfen: in N. J. Jacquin, Misc. Austriac. 1: 147, plate 17, fig. 1. (1778) |
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