Draba alpina |
Draba spectabilis |
|
---|---|---|
alpine Draba |
showy Draba, showy whitlowgrass |
|
Habit | Perennials; (cespitose); caudex branched (covered with persistent leaves or leaf remains); scapose. | Perennials; caudex simple or branched (sometimes with persistent leaf bases); not scapose. |
Stems | 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. |
unbranched, (0.7–)1.1–3.7(–5.3) dm, pubescent throughout (sparsely so distally), trichomes simple, malpighiaceous, or sessile and 4-rayed, 0.15–0.5 mm, (2 rays parallel to stem axis longer). |
Basal leaves | 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. |
rosulate; petiolate; petiole sometimes ciliate, (trichomes simple); blade oblanceolate to spatulate or obovate, (1–)1.5–4.4(–6.3) cm × (3–)5–12(–15) mm, margins entire or dentate, surfaces pubescent with sessile, often 4-rayed trichomes, 0.1–0.6 mm (longest rays parallel to midvein, lateral rays sometimes reduced to tiny spurs), sometimes malpighiaceous trichomes present. |
Cauline leaves | 0. |
4–12(–17); sessile; blade broadly ovate to lanceolate or oblong, margins entire or dentate, (ciliate or not), surfaces pubescent as basal or adaxially also with simple trichomes. |
Racemes | 6–18-flowered, ebracteate, considerably elongated in fruit; rachis not flexuous, pubescent as stem. |
(10–)16–49(–61)-flowered, ebracteate, elongated in fruit; rachis not flexuous, pubescent as stem. |
Flowers | 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. |
sepals ovate, (2.2–)2.5–4 mm, glabrous or pubescent, (trichomes simple and malpighiaceous); petals yellow, oblanceolate, 4–6.5 × 1–2.5 mm; anthers oblong, 0.5–0.7 mm. |
Fruiting pedicels | ascending to divaricate-ascending, straight or, sometimes, slightly curved upwards, 4–14(–30) mm, pubescent, trichomes simple and 2–4-rayed. |
horizontal to divaricate-ascending, straight or curved upward, (5–)7–20(–26) mm, glabrous or pubescent as rachis abaxially. |
Fruits | 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). |
lanceolate to oblong or elliptic, plane, flattened, (6–)7–13 × 2–3.5 mm; valves glabrous or puberulent, trichomes simple and sessile, 2-rayed, 0.03–0.3 mm; ovules 12–24 per ovary; style (0.5–)1–2.7 mm. |
Seeds | (pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm. |
ovoid, 1–1.4 × 0.7–0.9 mm. |
2n | = 80. |
= 40. |
Draba alpina |
Draba spectabilis |
|
Phenology | Flowering Jun–Aug. | Flowering Jun–Aug. |
Habitat | Moist tundra and ridges, sand and gravel flats or beaches | Talus, rocky hillsides, meadows in open conifer forests, aspen groves, and alpine communities |
Elevation | 0-1000 m (0-3300 ft) | 2000-3900 m (6600-12800 ft) |
Distribution |
LB; MB; NU; ON; QC; Greenland; Europe (Finland, Norway, Russia, Sweden)
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CO; NM; WY
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Discussion | 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.) |
Morphological and chromosomal data suggest that Draba spectabilis is an allopolyploid resulting from hybridization between D. abajoensis and D. malpighiacea. The characteristics distinguishing these three taxa were discussed in detail by I. A. Al-Shehbaz and M. D. Windham (2007). Chromosome counts attributed to D. spectabilis by Windham (2000) represent diploid D. abajoensis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 7, p. 290. | FNA vol. 7, p. 339. |
Parent taxa | Brassicaceae > tribe Arabideae > Draba | Brassicaceae > tribe Arabideae > Draba |
Sibling taxa | ||
Synonyms | D. alpina var. hydeana, D. alpina var. inflatisiliqua | D. oxyloba, D. spectabilis var. bella, D. spectabilis var. oxyloba, D. spectabilis var. purpusii |
Name authority | Linnaeus: Sp. Pl. 2: 642. (1753) | Greene: Pittonia 4: 19. (1899) |
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