Draba globosa |
Draba pectinipila |
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beavertip Draba, rockcress Draba, round-fruit Draba |
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Habit | Perennials; (cespitose, pulvinate); caudex branched (with persistent leaves, branches sometimes terminating in sterile rosettes); scapose. | Perennials; (cespitose, sometimes forming mats); caudex branched (with persistent leaf bases, branches creeping, terminating in scapes or sterile rosettes); scapose. |
Stems | unbranched, 0.1–0.5 dm, glabrous. |
unbranched, (0.3–)0.4–1.6(–1.9) dm, pubescent, trichomes sessile, pectinate, 0.1–0.4 mm, (parallel to long axis of stem, sometimes with irregularly 2–4-rayed ones, 0.2–0.6 mm). |
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). |
rosulate; subsessile; blade narrowly oblanceolate to linear, (0.4–)0.6–1.3(–2) cm × 0.9–2.2 mm, margins entire (not ciliate), surfaces pubescent with subsessile or sessile, pectinate trichomes, 0.2–0.5 mm. |
Cauline leaves | 0. |
0. |
Racemes | 2–5(–7)-flowered, ebracteate, slightly elongated in fruit; rachis not flexuous, glabrous. |
5–22-flowered, ebracteate, considerably 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 broadly ovate, 2–3.2 mm, pubescent, (trichomes pectinate); petals yellow, obovate to spatulate, 4–6.5 × 1.5–2.5 mm; anthers ovate 0.4–0.5 mm. |
Fruiting pedicels | divaricate-ascending, straight or slightly curved, 2–6 mm, glabrous. |
divaricate-ascending, straight, (5–)7–14 mm, sparsely pubescent, trichomes pectinate. |
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. |
ovoid, plane, slightly inflated basally, 4–6(–7) × 2–3 mm; valves pubescent, trichomes usually sessile, pectinate, 0.2–0.5 mm, rarely with simple ones; ovules 4–8 per ovary; style 0.5–1.5 mm. |
Seeds | oblong, 1.1–1.4 × 0.8–1 mm. |
oblong, 1.1–1.5 × 0.6–0.8 mm. |
2n | = 22. |
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Draba globosa |
Draba pectinipila |
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Phenology | Flowering Jun–Aug. | Flowering Apr–Jun. |
Habitat | Ridges, talus, alpine tundra and meadows | Rocky slopes in sagebrush scrub and pinyon-juniper woodlands |
Elevation | 2700-3900 m (8900-12800 ft) | 1700-2400 m (5600-7900 ft) |
Distribution |
ID; MT; UT; WY
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CO; MT; UT; WY |
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.) |
Draba pectinipila was treated as a synonym of D. oligosperma by G. A. Mulligan (1972), R. C. Rollins (1993), and N. H. Holmgren (2005b). The latter recognized D. juniperina as a distinct species but overlooked the fact that it is indistinguishable from the type collections of the earlier-published D. pectinipila. The species (including D. juniperina) differs significantly from D. oligosperma in both chromosome number and morphology. Draba pectinipila is easily distinguished by having fruit valves pubescent with pectinate trichomes, fruiting pedicels (5–)7–14 mm, petals 4–6.5 mm, ovules 4–8 per ovary, and styles 0.5–1.5 mm. By contrast, D. oligosperma has fruit valves glabrous or pubescent with simple or 2-rayed trichomes, fruiting pedicels (2–)3–10(–13) mm, petals 2.5–4 mm, ovules 6–12 per ovary, and styles 0.1–0.8(–1.1) mm. Draba pectinipila was previously known only from the type locality in northwestern Wyoming (Park County). Its range is now expanded to include that of D. juniperina in northwestern Colorado (Moffat County), northeastern Utah (Daggett and Uintah counties), and southwestern Wyoming (Sweetwater County). The record from Uintah County is based on Goodrich 22275 (NY). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 308. | FNA vol. 7, p. 328. |
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 | D. juniperina, D. oligosperma var. juniperina, D. oligosperma var. pectinipila |
Name authority | Payson: Amer. J. Bot. 4: 257. (1917) | Rollins: Rhodora 55: 231. (1953) |
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