Draba oreibata |
Draba sphaeroides |
|
---|---|---|
limestone Draba |
ball Draba |
|
Habit | Perennials; (cespitose); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose, densely pulvinate); caudex branched (branches often tangled with persistent leaf remnants, prostrate, slender, sometimes terminating in sterile rosettes); scapose. |
Stems | unbranched, 0.2–0.9 dm, glabrous throughout. |
unbranched, (0.2–)0.3–0.8 dm, sparsely pubescent proximally, glabrous distally, trichomes usually 2- or 3-rayed, rarely some simple, 0.1–0.25 mm. |
Basal leaves | rosulate; sessile; blade oblong to narrowly oblanceolate, 0.2–1 cm × 0.6–2(–4) mm, margins entire, (ciliate, trichomes simple, 0.1–0.5 mm, apex obtuse), surfaces glabrous. |
not rosulate; subsessile; petiole margins not ciliate; blade oblanceolate to oblong or elliptic, 0.3–0.8(–0.9) cm × (1–)1.5–3(–4) mm, margins entire, (not ciliate), surfaces usually pubescent, rarely both surfaces glabrous (except margin), with stalked, 2–4-rayed trichomes, 0.07–0.4 mm (or, rarely, trichomes mostly simple and 2-rayed adaxially). |
Cauline leaves | 0. |
0. |
Racemes | 3–8-flowered, ebracteate, considerably elongated in fruit; rachis slightly flexuous, glabrous. |
(3–)5–11(–14)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous or sparsely pubescent as stem. |
Flowers | sepals oblong, 1.7–2.5 mm, glabrous; petals white, oblanceolate to obovate, 3.5–4.5 × 1.2–2 mm; anthers ovate, 0.3–0.4 mm. |
sepals broadly ovate, 1.7–2.5 mm, glabrous or sparsely pubescent, (trichomes simple and short-stalked, 2- or 3-rayed); petals yellow, spatulate, 2.7–4 × 1.5–2.2 mm; anthers ovate, 0.4–0.5 mm. |
Fruiting pedicels | divaricate-ascending to ascending, straight, 4–13 mm, glabrous. |
divaricate-ascending, straight or curved upward, (sometimes slightly expanded basally), 3–8 mm, usually glabrous, rarely sparsely pubescent, trichomes simple and 2- or 3-rayed. |
Fruits | oblong to narrowly so, slightly twisted, flattened, 5–9 × 1.5–3 mm; valves glabrous; ovules 8–16 per ovary; style 0.3–0.9(–1.2) mm. |
broadly lanceolate to ellipsoid or ovoid, plane, inflated at least basally, (2.5–)3.5–7(–8) × (1.5–)2–3.5 mm; valves glabrous or sparsely pubescent, trichomes simple and short-stalked, 2(–4)-rayed, 0.07–0.2 mm; ovules 4–10(–12) per ovary; style 0.3–1(–1.3) mm. |
Seeds | oblong, 0.9–1.3 × 0.6–0.8 mm. |
oblong, 1–1.5 × 0.8–1 mm. |
2n | = 32. |
= 20. |
Draba oreibata |
Draba sphaeroides |
|
Phenology | Flowering May–Jul. | Flowering Jun–Aug. |
Habitat | Limestone cliffs, talus | Rock outcrops, talus, soil pockets on rocky slopes |
Elevation | 1800-2700 m (5900-8900 ft) | 2500-3300 m (8200-10800 ft) |
Distribution |
ID |
NV |
Discussion | R. C. Rollins (1993) and N. H. Holmgren (2005b) divided Draba oreibata into two varieties: the Idaho endemic var. oreibata and the Nevada endemic var. serpentina. As indicated by I. A. Al-Shehbaz and M. D. Windham (2007), the two taxa are morphologically distinct, have different chromosome numbers, and are separated by over 480 kilometers. They are treated herein as separate species, and distinguished by characteristics discussed by Al-Shehbaz and Windham. Draba oreibata, in the strict sense, is known from Blaine, Butte, Clark, Custer, and Lemhi counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Draba sphaeroides is closely related to D. pedicellata; the two are easily distinguished using the characteristics discussed by M. D. Windham (2004). The species is known from Elko County (East Humboldt, Ruby and Jarbidge mountains) in northeastern Nevada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 325. | FNA vol. 7, p. 339. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. oligosperma var. sphaeroides | |
Name authority | J. F. Macbride & Payson: Amer. J. Bot. 4: 257. (1917) | Payson: Amer. J. Bot. 4: 265. (1917) |
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