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FNA | Family List | FNA Vol. 7 | Brassicaceae | Draba

111. Draba streptocarpa A. Gray, Amer. J. Sci. Arts, ser. 2. 33: 242. 1862.

Draba streptocarpa var. tonsa (Wooton & Standley) O. E. Schulz; D. tonsa Wooton & Standley

Perennials; (tufted); caudex simple or branched (covered with persistent leaf remains); not scapose. Stems usually unbranched, (0.2-)0.4-2.5 dm, hirsute proximally, sparsely pubescent or glabrous distally or throughout, trichomes simple, 0.4-2.2 mm, often with stalked, 2(-4)-rayed ones, 0.2-1 mm. Basal leaves rosulate; blade oblong-oblanceolate to linear-oblanceolate, 0.5-3.8 cm × 1.5-6 mm, margins entire, (ciliate, trichomes setiform, simple, 0.6-2.8 mm), surfaces strigose to hirsute abaxially with long-stalked, 2(-4)-rayed trichomes, 0.4-1.4 mm, usually with simple ones, strigose adaxially with simple trichomes, 0.7-2.4 mm. Cauline leaves 2-15; sessile; blade oblong to lanceolate, margins entire, surfaces pubescent as basal. Racemes 9-62-flowered, ebracteate or proximalmost 1-3 flowers bracteate, elongated in fruit; rachis not flexuous, sparsely pubescent as stem or glabrous. Fruiting pedicels ascending, slightly curved or straight, 4-12 mm, glabrous or pubescent abaxially, trichomes simple (0.4-1.6 mm). Flowers: sepals oblong, 2.5-3.5 mm, usually pubescent, rarely glabrous, (trichomes simple, sometimes with stalked, 2-rayed ones); petals yellow, oblanceolate to spatulate, (4-)5-7.5 × 1-2(-2.5) mm; anthers ovate, 0.5-0.7 mm. Fruits ovate to linear-lanceolate, usually strongly twisted (to 3 turns), rarely plane, flattened, 5-16 × 2-3 mm; valves puberulent along margin, trichomes simple, 0.05-0.3 mm; ovules 20-34 per ovary; style (0.8-) 1-2(-2.5) mm. Seeds ovoid, 0.9-1.2 × 0.6-0.7 mm. 2n = 20, 40.

Flowering May-Jul. Rock outcrops, hillsides and meadows in open mixed conifer forests, aspen groves, and alpine tundra communities; 2400-4000 m; Colo., N.Mex., Wyo.

Draba streptocarpa is easily recognized by its strongly twisted fruits and broad-based, simple cilia on the basal leaves. It is found primarily in Colorado, but has also been collected in Larimer County, Wyoming, and Mora, San Miguel, and Taos counties, New Mexico.


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