Draba alpina
Draba bifurcata
alpine Draba
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.
branched or unbranched, 1–3.9 dm, pubescent throughout or proximally, trichomes simple, 0.3–1.4 mm, often with smaller, 2 (or 3)-rayed ones.
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.
(soon withered); rosulate; petiolate;
petiole ciliate, (trichomes simple, 0.4–1.1 mm);
blade oblanceolate to spatulate, 1–7 cm × 2–12(–26) mm, margins entire or dentate (pubescent as petiole), surfaces pubescent, abaxially with simple trichomes, 0.6–1.1 mm, and stalked, 2- (or 3-)rayed ones, often smaller, adaxially with subsetiform, simple trichomes, 0.5–1.2 mm (rarely with fewer, stalked, 2-rayed ones).
0.
(2–)6–15;
sessile;
blade lanceolate to ovate or oblong, margins dentate, surfaces pubescent as basal.
6–18-flowered, ebracteate, considerably elongated in fruit;
rachis not flexuous, pubescent as stem.
10–51-flowered, ebracteate, elongated in fruit;
rachis glabrous or pubescent as stem, not flexuous.
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, 2.5–3.2 mm, pubescent, (trichomes simple and short-stalked, 2-rayed);
petals yellow, oblanceolate, 4.5–6.5 × 1.5–2 mm;
anthers oblong, 0.8–1.1 mm.
ascending to divaricate-ascending, straight or, sometimes, slightly curved upwards, 4–14(–30) mm, pubescent, trichomes simple and 2–4-rayed.
horizontal to divaricate, straight, 4–15 mm, glabrous or pubescent, trichomes simple and 2-rayed.
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).
elliptic-lanceolate, twisted (1 turn or plane), flattened, 6–10 × 2–2.5 mm;
valves glabrous or sparsely puberulent, trichomes simple, 0.05–0.15 mm;
ovules 14–20 per ovary;
style (1–)2–3 mm.
(pale brown), ovoid, 0.9–1.3 × 0.6–0.9 mm.
oblong, 1.1–1.4 × 0.7–0.9 mm.
= 80.
Draba alpina
Draba bifurcata
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.)
Draba bifurcata is distinguished from other North American species by a combination of yellow flowers with styles (1–)2–3 mm and almost exclusively simple trichomes on the abaxial surface of cauline leaf blades. It is known only from Chiricahua, Santa Catalina, and White mountains in Apache, Cochise, and Pima counties.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
WildflowerSearch
iNaturalist
USDA Plants Database
