Draba globosa |
Draba pennellii |
|
---|---|---|
beavertip Draba, rockcress Draba, round-fruit Draba |
schell creek Draba |
|
Habit | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose, often forming mats); caudex branched (elongated, with persistent leaf bases, branches sometimes terminating in sterile rosettes); sometimes scapose. |
Stems | unbranched, 0.1–0.5 dm, glabrous. |
unbranched, (0.15–)0.3–0.7(–1) dm, pubescent proximally, trichomes simple and spurred, 0.4–0.8 mm, and short-stalked, 2–4-rayed, 0.1–0.4 mm, (sometimes with simple trichomes distally). |
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). |
subrosulate; sessile; blade oblanceolate to oblong, (0.3–)0.5–0.8 cm × 1–3 mm, (base ciliate, trichomes simple, 0.2–0.8 mm), margins entire, (not ciliate), surfaces usually pubescent, with stalked, (2–)4 (or 5)-rayed trichomes, 0.2–0.5 mm, adaxially sometimes glabrate, or primarily with simple trichomes, 0.3–0.8 mm. |
Cauline leaves | 0. |
(0 or) 1–4; sessile; blade ovate to oblong, margins entire, surfaces pubescent as basal. |
Racemes | 2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
(3–)7–15(–20)-flowered, ebracteate, 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 ovate to oblong, 2–3 mm, pubescent, (trichomes simple, with fewer, short-stalked, 2-rayed ones); petals white, obovate, 3.5–6 × 1.5–2.8 mm; anthers oblong, 0.5–0.6 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
divaricate-ascending to ascending, straight, 3–10 mm, pubescent, trichomes simple and short-stalked, 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. |
broadly or, rarely, narrowly lanceolate to elliptic or ovate, plane or slightly twisted, flattened, (4)5–8(–10) × 2–3.2 mm; valves (each with distinct midvein), pubescent, trichomes simple and short-stalked, 2-rayed, 0.08–0.2 mm; ovules 12–24 per ovary; style (0.7–)1–1.8(–2.1) mm. |
Seeds | oblong, 1.1–1.4 × 0.8–1 mm. |
oblong, 0.9–1.3 × 0.7–1 mm. |
2n | = 32. |
|
Draba globosa |
Draba pennellii |
|
Phenology | Flowering Jun–Aug. | Flowering May–Jul. |
Habitat | Ridges, talus, alpine tundra and meadows | Rock outcrops and talus slopes in pinyon-juniper, sagebrush, mountain shrub, and mixed conifer communities |
Elevation | 2700-3900 m (8900-12800 ft) | 1900-3500 m (6200-11500 ft) |
Distribution |
ID; MT; UT; WY
|
NV |
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.) |
Of conservation concern. Draba pennellii is known from White Pine County in east-central Nevada. It is easily distinguished from other white-flowered species in the region by its elongated, many-branched caudices, long styles, usually few-leaved or, rarely, leafless flowering stems, and distinct midvein on fruit valves. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 308. | FNA vol. 7, p. 329. |
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 | |
Name authority | Payson: Amer. J. Bot. 4: 257. (1917) | Rollins: J. Arnold Arbor. 64: 502. (1983) |
Web links |