Draba exunguiculata |
Draba longisquamosa |
|
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clawless Draba |
granite Draba |
|
Habit | Perennials; (densely cespitose); caudex branched (covered with persistent, somewhat thickened, dry petioles); not scapose. | Perennials; (cespitose); caudex branched (covered with persistent petiole remains, branches sometimes terminating in sterile rosettes); scapose. |
Stems | unbranched, 0.15–0.7 dm, glabrous throughout or sparsely pubescent, trichomes simple, 0.3–0.9 mm. |
unbranched, 0.2–0.9 dm, hirsute throughout, trichomes simple, 0.2–0.8 mm. |
Basal leaves | rosulate; petiolate; petiole ciliate, (trichomes simple, 0.3–1.1 mm); blade linear to linear-oblanceolate, (0.5–)0.8–2(–2.5) cm × 1–3 mm, margins entire, (pubescent as petiole), surfaces abaxially sparsely pubescent with simple and stalked, 2- or 3-rayed trichomes, 0.1–0.4 mm, adaxially glabrous or subapically sparsely pubescent with simple trichomes. |
rosulate; shortly petiolate; petiole base and margin ciliate, (trichomes simple, 0.1–1 mm); blade oblanceolate to obovate, 0.5–2 cm × 2–5 mm, margins entire, surfaces pubescent with simple trichomes, 0.15–0.8 mm. |
Cauline leaves | 1–4; sessile; blade linear to linear-oblanceolate, margins entire, surfaces pubescent as basal. |
0. |
Racemes | 4–13(–20)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely sparsely pubescent, trichomes simple, to 1 mm. |
4–16-flowered, ebracteate, (subumbellate), slightly elongated in fruit; rachis not flexuous, hirsute as stem. |
Flowers | sepals ovate, 2–2.5 mm, pubescent, (trichomes simple); petals (erect), yellow, obovate, 2–2.5(–3) × 1.5–2 mm, (not clawed); anthers oblong, 0.6–0.9 mm. |
sepals (persistent) ovate, 1.5–2.2 mm, pubescent, (trichomes simple); petals (persistent), yellow, spatulate, 3.5–5 × 1.5–2 mm; anthers oblong, 0.5–0.6 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved upward, 1–6 mm, usually glabrous, rarely with few, simple trichomes. |
divaricate to ascending (not decurrent basally), straight, 3–7 mm, hirsute as stem. |
Fruits | lanceolate to oblong-lanceolate, plane, flattened, 5–13 × 1.5–3 mm; valves glabrous; ovules 20–24 per ovary; style 0.3–1 mm. |
ovate to suborbicular, plane, flattened, 3.5–7 × 2.5–5 mm; valves pubescent, trichomes simple, 0.1–0.3 mm; ovules 10–16 per ovary; style 0.4–1 mm. |
Seeds | ovoid, 1–1.3 × 0.6–0.8 mm. |
ovoid, 1–1.2 × 0.7–0.8 mm. |
2n | = 56 ± 5. |
|
Draba exunguiculata |
Draba longisquamosa |
|
Phenology | Flowering Jul–Aug. | Flowering Jul. |
Habitat | Open knolls, talus, gravelly alpine slopes, rocky alpine tundra | Gravelly areas |
Elevation | 3600-4300 m (11800-14100 ft) | 3000-3900 m (9800-12800 ft) |
Distribution |
CO |
CA |
Discussion | Of conservation concern. Draba exunguiculata occupies alpine areas of Clear Creek, El Paso, Grand, and Summit counties in central Colorado. Draba grayana is found in the same general area; both species are apomicts that occasionally grow sympatrically. Draba exunguiculata is easily distinguished from D. grayana by having stems and fruiting pedicels glabrous or sparsely pubescent with simple trichomes (versus moderately to densely pubescent with simple and 2- or 3-rayed trichomes), and by having erect, non-clawed petals, 2–3 mm and slightly longer than sepals (versus flared, clawed petals 3–4.5 mm and nearly twice as long as sepals). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Draba longisquamosa was treated as a synonym of D. lemmonii by both C. L. Hitchcock (1941) and R. C. Rollins (1993). We feel that the two taxa show sufficient morphological divergence and merit recognition as separate species (see I. A. Al-Shehbaz and M. D. Windham 2007 for more detailed discussion). Draba longisquamosa is currently known only from the southern Sierra Nevada in Fresno, Inyo, and Tulare counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 306. | FNA vol. 7, p. 317. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. chrysantha var. exunguiculata, D. chrysantha | |
Name authority | (O. E. Schulz) C. L. Hitchcock: Revis. Drabas W. N. Amer., 46. (1941) | O. E. Schulz: in H. G. A. Engler, Pflanzenr. 89[IV,105]: 94. (1927) |
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