Draba ramulosa |
Draba alpina |
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Tushar Mountain Draba |
alpine Draba |
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Habit | Perennials; (loosely matted, grayish); caudex branched (with persistent leaf bases, branches creeping, sometimes terminating in sterile rosettes); not scapose. | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. |
Stems | unbranched, 0.4–0.6 dm, densely pubescent throughout, trichomes dendritic, 3–6-rayed, (often crisped), 0.1–0.4 mm. |
unbranched, (0.3–)0.5–1.7(–2.8) dm, pubescent throughout, trichomes simple and 2-rayed, 0.3–0.8 mm, with 3–5-rayed ones, 0.1–0.3 mm. |
Basal leaves | (imbricate); not rosulate; sessile; blade obovate to oblanceolate, 0.4–1.1 cm × 2–3.2 mm, margins entire, (base and margins not ciliate), surfaces pubescent with stalked, 4–8-rayed trichomes, 0.1–0.5 mm, (sometimes 1 or more rays spurred), adaxially sometimes trichomes simple. |
rosulate; petiolate; petiole base (not thickened), ciliate, (trichomes simple, 0.3–1 mm); blade oblanceolate to obovate or lanceolate to oblong, 0.8–3(–4.5) cm × 2.5–6(–9) mm, margins entire, surfaces abaxially pubescent with stalked, 2–4-rayed trichomes, 0.1–0.5 mm, with simple ones (midvein obscure, not thickened), adaxially glabrous or sparsely pubescent with simple and stalked, 2–4-rayed trichomes. |
Cauline leaves | 2 or 3 (sometimes basal leaves spaced, flowering stem appearing to 8-leaved); sessile; blade oblong to ovate, margins entire, surfaces pubescent as basal. |
0. |
Racemes | 4–15-flowered, ebracteate or proximalmost 1 or 2 flowers bracteate, slightly elongated in fruit; rachis not flexuous, pubescent as stem. |
6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | sepals broadly ovate, 1.7–2.4 mm, pubescent, (trichomes short-stalked, 2–5-rayed); petals yellow, obovate to oblanceolate, 3–4.5 × 1.5–2.5 mm; anthers ovate, 0.4–0.5 mm. |
sepals (purplish tinged), narrowly ovate, 2.5–3 mm, pubescent, (trichomes simple and fewer, stalked, 2-rayed); petals bright yellow, narrowly obovate, 3.5–5 × 1.7–2.5 mm; anthers ovate, 0.3–0.4 mm. |
Fruiting pedicels | divaricate-ascending, usually straight, rarely curved upward, 3–6(–10) mm, pubescent, trichomes 3–6-rayed, (crisped, 0.1–0.4 mm), and, sometimes, simple. |
ascending to divaricate-ascending, straight or, sometimes, slightly curved upwards, 4–14(–30) mm, pubescent, trichomes simple and 2–4-rayed. |
Fruits | (not appressed to rachis), ovate to elliptic, plane, flattened, 4–6.5 × 2.5–4 mm; valves densely pubescent, trichomes simple and short-stalked, 2–5-rayed, 0.08–0.35 mm; ovules 6–12 per ovary; style (0.1–)0.3–0.7 mm. |
elliptic, plane, flattened, 6–10 × 2–3 mm; valves glabrous or glabrescent, trichomes simple, (not confined to replum); ovules 12–24 per ovary; style 0.2–0.3 mm (stigma about as wide as style). |
Seeds | oblong, 1.4–1.8 × 0.8–1.2 mm. |
(pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
2n | = 80. |
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Draba ramulosa |
Draba alpina |
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Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Rock outcrops, talus, gravelly soils | Moist tundra and ridges, sand and gravel flats or beaches |
Elevation | 3300-3600 m (10800-11800 ft) | 0-1000 m (0-3300 ft) |
Distribution |
UT |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
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Discussion | Of conservation concern. Molecular and chromosomal data (M. D. Windham, unpubl.) strongly suggest that Draba ramulosa is an allopolyploid species. It is thought to have originated through hybridization between D. sobolifera and a member of the white-flowered, euploid lineage of M. A. Beilstein and M. D. Windham (2003). It is easily distinguished from D. sobolifera by having pale yellow to whitish (versus bright yellow) petals, grayish (versus green) foliage, non-ciliate (versus ciliate) basal leaves pubescent with 4–8-rayed (versus 2–4-rayed) trichomes, often proximally bracteate (versus ebracteate) racemes, and flattened (versus inflated basally) fruits. Draba ramulosa is known from the Tushar Mountains in south-central Utah (Beaver and Piute counties). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The synonymy above includes two North American names overlooked by C. L. Hitchcock (1941) and R. C. Rollins (1993). Draba alpina was broadly delimited by O. E. Schulz (1927) and included 17 varieties, some of which (e.g., corymbosa, oxycarpa, pilosa) are recognized herein as distinct species. The name D. alpina was so misapplied that it was used for any circumpolar or alpine, scapose, yellow-flowered, perennial Draba. Various chromosome numbers (e.g., 2n = 64, 80, 112, 120; S. I. Warwick and I. A. Al-Shehbaz 2006) have been reported for the species. As circumscribed here, it has the narrow distribution outlined above and includes plants with 2n = 80. Reports of the species from Alaska, Canadian Northwest Territories and Yukon, Siberia, eastern Asia, Russian Far East, and the Central Asian republics are either suspect or very unlikely. The entire D. alpina complex (including the above three species, D. glacialis Adams, D. macounii, etc.) is in need of critical molecular, cytological, and morphological study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 332. | FNA vol. 7, p. 290. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | |
Name authority | Rollins: Contr. Gray Herb. 214: 6. (1984) | Linnaeus: Sp. Pl. 2: 642. (1753) |
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