Draba globosa |
Draba oxycarpa |
|
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beavertip Draba, rockcress Draba, round-fruit Draba |
|
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Habit | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose); caudex branched (covered with persistent petiole remains); scapose. |
Stems | unbranched, 0.1–0.5 dm, glabrous. |
unbranched, 0.2–1.1 dm, pubescent proximally, trichomes short-stalked, 2–5-rayed, 0.1–0.5 mm, (some rays spurred). |
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; petiole base and margin ciliate, (trichomes simple, 0.3–1 mm); blade oblanceolate to lanceolate, 0.8–2.2 cm × 2–6 mm, margins often entire, surfaces pubescent abaxially with stalked, 2–5-rayed, stellate trichomes, 0.1–0.4 mm, often some rays spurred and trichomes appearing subdendritic, rarely glabrate, or with simple and 2-rayed ones, (midvein obscure abaxially, not thickened), adaxially glabrous or sparsely pubescent with simple trichomes, sometimes with long-stalked, 2- or 3-rayed ones. |
Cauline leaves | 0. |
0. |
Racemes | 2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
(2–)4–13-flowered, ebracteate, (subcorymbose), not elongated in fruit; rachis not flexuous, pubescent as stem. |
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 (grayish white), ovate to broadly so, 2.5–3 mm, pubescent, (trichomes simple and stalked, 2-rayed); petals creamy white to yellow, broadly obovate, 3.5–5 × 2.5–3.5 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
subhorizontal to divaricate-ascending (not appressed to rachis), often slightly curved upward, 4–7(–10) mm, pubescent, trichomes simple (0.4–1 mm), and 2–4-rayed (0.1–0.4 mm). |
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. |
ovate to ovate-oblong, plane, flattened, 5–10 × 3–5 mm; valves puberulent along replum, trichomes simple, 0.1–0.3 mm; ovules (16–)18–28 per ovary; style 0.2–0.6 mm (stigma as wide as style). |
Seeds | oblong, 1.1–1.4 × 0.8–1 mm. |
(black), ovoid, 1–1.3 × 0.6–0.8 mm. |
2n | = 64. |
|
Draba globosa |
Draba oxycarpa |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Jul. |
Habitat | Ridges, talus, alpine tundra and meadows | Rocky soils |
Elevation | 2700-3900 m (8900-12800 ft) | |
Distribution |
ID; MT; UT; WY
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Greenland; Europe (Norway [including Spitsbergen], Sweden); Atlantic Islands (Iceland) |
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 oxycarpa is an octoploid that most closely resembles the decaploid D. alpina. It is distinguished from that species by having creamy white to pale yellow (versus bright yellow) petals, gray-green (versus purplish tinged) sepals, petals 2.5–3.5 (versus 1.7–2.5) mm wide, stems pubescent proximally with primarily branched (versus primarily simple) trichomes, nearly black (versus pale brown) seeds, and ovate to ovate-oblong (versus elliptic) fruits 3–5 (versus 2–3) mm wide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 308. | FNA vol. 7, p. 325. |
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. alpina var. oxycarpa, D. gredinii |
Name authority | Payson: Amer. J. Bot. 4: 257. (1917) | Sommerfelt: Mag. Naturvidensk., n. s. 1: 240. (1833) |
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