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

26. Boechera evadens Windham & Al-Shehbaz, Harvard Pap. Bot. 11: 66. 2006.

Perennials; long-lived; (ces-pitose); sexual; caudex woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 1-2.5 dm, densely pubescent proximally, trichomes short-stalked, 2-5-rayed, 0.2-0.6 mm, and sparse, simple ones to 1 mm, glabrous distally. Basal leaves: blade narrowly oblanceolate, 1.5-3 mm wide, margins entire, ciliate along petiole, trichomes (simple), to 1 mm, surfaces densely pubescent, trichomes short-stalked, 4-8-rayed, 0.1-0.2 mm. Cauline leaves: 3-5, not concealing stem; blade auricles 0.5-1 mm, surfaces of distalmost leaves pubescent. Racemes 10-22-flowered, unbranched. Fruiting pedicels divaricate-ascending, straight, 4-8 mm, sparsely pubescent, trichomes appressed, branched. Flowers ascending at anthesis; sepals pubescent; petals white, 3-4 × 0.5-0.8 mm, glabrous; pollen ellipsoid. Fruits divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 3-4 cm × 1.2-1.5 mm; valves glabrous; ovules 46-52 per ovary; style ca. 0.1 mm. Seeds uniseriate, 1-1.1 × 0.9-1 mm; wing continuous, ca. 0.1 mm wide.

Flowering Jun. Rock outcrops; ca. 2600 m; Calif.

Boechera evadens is a sexual taxon that was originally interpreted as a disjunct population of Arabis (Boechera) fernaldiana, but is easily distinguished from that species by having much shorter (3-4 versus 7-12 mm) petals, larger (0.2-0.6 versus 0.04-0.1 mm) trichomes proximally on stems, and shorter (3-4 versus 4-7.5 cm) fruits (see M. D. Windham and I. A. Al-Shehbaz 2006 for additional distinctions). It is known only from the holotype specimen collected near Sherman Pass in Tulare County.


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