Draba exunguiculata |
Draba aprica |
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clawless Draba |
hairy Draba, openground Draba |
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Habit | Perennials; (densely cespitose); caudex branched (covered with persistent, somewhat thickened, dry petioles); not scapose. | Annuals; not scapose. |
Stems | unbranched, 0.15–0.7 dm, glabrous throughout or sparsely pubescent, trichomes simple, 0.3–0.9 mm. |
usually branched distally, (0.3–)0.7–3(–3.6) dm, pubescent throughout, trichomes short-stalked to subsessile, cruciform, 0.1–0.5 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. |
not rosulate; petiolate; petiole (to 1 cm), ciliate throughout; blade obovate to spatulate or ovate to suborbicular, 0.6–2.5 cm × 3–10 mm, margins usually entire, rarely toothed, surfaces pubescent with stalked, cruciform trichomes, 0.1–0.5 mm. |
Cauline leaves | 1–4; sessile; blade linear to linear-oblanceolate, margins entire, surfaces pubescent as basal. |
(5–)8–20(–25); sessile; blade oblong to lanceolate, margins entire, (not ciliate), surfaces pubescent as basal. |
Racemes | 4–13(–20)-flowered, ebracteate, elongated in fruit; rachis not flexuous, usually glabrous, rarely sparsely pubescent, trichomes simple, to 1 mm. |
7–46-flowered, ebracteate, elongated in fruit, (lateral racemes from axils of distalmost leaves subumbellate); rachis not flexuous, pubescent 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. |
(late ones cleistogamous, apetalous); sepals oblong, 0.6–1.2 mm, pubescent; petals white, spatulate, 1.3–2.5 × 0.5–1 mm; anthers ovate, 0.1–0.2(–0.05 in cleistogamous flowers) mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved upward, 1–6 mm, usually glabrous, rarely with few, simple trichomes. |
horizontal to divaricate-ascending, straight, 2–5 mm, pubescent, trichomes subsessile, 4-rayed. |
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. |
linear-ellipsoid to ellipsoid, plane, flattened, (3–)4–6 × 0.8–1.1 mm; valves pubescent, trichomes subsessile, (2–)4-rayed, 0.03–0.12 mm; ovules 4–6(–8) per ovary; style 0.07–0.13 mm. |
Seeds | ovoid, 1–1.3 × 0.6–0.8 mm. |
ovoid, 0.9–1.1 × 0.5–0.6 mm. |
2n | = 56 ± 5. |
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Draba exunguiculata |
Draba aprica |
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Phenology | Flowering Jul–Aug. | Flowering Mar–May. |
Habitat | Open knolls, talus, gravelly alpine slopes, rocky alpine tundra | Open knolls, rocky roadsides, rock outcrops, igneous glades, woods, alluvial areas near streams |
Elevation | 3600-4300 m (11800-14100 ft) | 100-400 m (300-1300 ft) |
Distribution |
CO |
AR; GA; MO; OK; SC
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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.) |
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Source | FNA vol. 7, p. 306. | FNA vol. 7, p. 290. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. chrysantha var. exunguiculata, D. chrysantha | D. brachycarpa var. fastigiata |
Name authority | (O. E. Schulz) C. L. Hitchcock: Revis. Drabas W. N. Amer., 46. (1941) | Beadle: in J. K. Small, Fl. S.E. U.S. ed. 2, 1336, 1375. (1913) |
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