Draba brachystylis |
Draba paucifructa |
|
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shortstyle Draba |
Charleston Mountain Draba |
|
Habit | Annuals or perennials; (short-lived); caudex often simple (poorly developed); not scapose. | Perennials; caudex simple or branched (not fleshy, usually with some persistent leaf remains); sometimes scapose. |
Stems | unbranched or branched, 0.6–3(–3.7) dm, pubescent throughout, trichomes simple, 0.4–0.9 mm, and 2–4-rayed, 0.05–0.4 mm. |
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. |
Basal leaves | rosulate; subsessile; petiole base ciliate, (trichomes simple, 0.3–0.9 mm); blade oblanceolate, 1–3.5 cm × 4–7(–12) mm, margins entire or denticulate, surfaces pubescent, abaxially with stalked, (2–)4-rayed trichomes, 0.1–0.5 mm, adaxially with simple trichomes, 0.2–0.6 mm, with smaller, 2–4-rayed ones. |
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. |
Cauline leaves | (1 or) 2–6(–8); sessile; blade lanceolate or oblanceolate to ovate, margins entire or denticulate, surfaces pubescent as basal. |
0 or 1; sessile; blade ovate to lanceolate, margins entire, surfaces pubescent as basal. |
Racemes | (5–)10–35(–47)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
(2–)4–9(–12)-flowered, ebracteate, elongated in fruit; rachis slightly flexuous, glabrous. |
Flowers | sepals ovate, 2–2.7 mm, pubescent, (trichomes simple and short-stalked, 2-rayed); petals pale yellow (fading white), oblanceolate, 2.5–3.7 × 0.9–1.2 mm; anthers ovate, 0.2–0.3 mm. |
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. |
Fruiting pedicels | divaricate-ascending, straight or only slightly curved upward, (1.5–)3–8(–10) mm, pubescent throughout, trichomes simple and stalked, 2–4-rayed. |
divaricate-ascending, straight, 2–5(–8) mm, glabrous. |
Fruits | narrowly elliptic to lanceolate, plane, flattened, (7–)10–16(–19) × 2–3.5 mm; valves pubescent, trichomes simple, spurred, and short-stalked, 2-rayed, 0.05–0.2(–0.3) mm; ovules 20–36(–42) per ovary; style 0.2–0.6(–0.8) mm. |
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. |
Seeds | oblong, 0.9–1.3 × 0.6–0.7 mm. |
oblong, 0.9–1.2 × 0.5–0.8 mm. |
2n | = 44. |
= 40. |
Draba brachystylis |
Draba paucifructa |
|
Phenology | Flowering Jun–Jul. | Flowering Jun–Jul. |
Habitat | Fir and aspen communities, moist areas on rocky slopes | Moist, shaded slopes among limestone and dolomite rocks |
Elevation | 1700-3000 m (5600-9800 ft) | 2600-3500 m (8500-11500 ft) |
Distribution |
UT |
NV |
Discussion | Of conservation concern. Based on morphological and chromosomal data (L. Allphin and M. D. Windham, unpubl.), Draba brachystylis is hypothesized to be an allopolyploid derived through hybridization between D. albertina and D. santaquinensis. It is known to us only from Cache, Duchesne, Juab, Salt Lake, and Utah counties. C. L. Hitchcock (1941) indicated that the species grows in the Charleston Mountains of Clark County, Nevada, but we have not seen unequivocal material of it from that area. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 297. | FNA vol. 7, p. 327. |
Parent taxa | ||
Sibling taxa | ||
Name authority | Rydberg: Bull. Torrey Bot. Club 29: 240. (1902) | Clokey & C. L. Hitchcock: Madroño 5: 127. (1939) |
Web links |