21. Boechera dispar (M. E. Jones) Al-Shehbaz, Novon. 13: 384. 2003.
Arabis dispar M. E. Jones, Contr. W. Bot. 8: 41. 1898; A. juniperina M. E. Jones; A. nardina Greene; A. salubris M. E. Jones
Perennials; usually long-lived; sexual; caudex often woody. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 0.9-3 dm, densely pubescent proximally, trichomes short-stalked, 5-12-rayed, 0.1-0.3 mm, sparsely pubescent to glabrescent distally. Basal leaves: blade linear-oblanceolate, 2-5 mm wide, margins entire, not ciliate, surfaces densely pubescent, trichomes short-stalked, 5-12(-16)-rayed, 0.1-0.3 mm. Cauline leaves: 1-5, not concealing stem; blade without auricles, surfaces of distalmost leaves pubescent. Racemes 4-15(-20) -flowered, unbranched. Fruiting pedicels ascending, straight, 4-15(-25) mm, pubescent, trichomes appressed, branched. Flowers ascending at anthesis; sepals pubescent; petals purple to lavender, 3.5-6 × 1-1.5 mm, glabrous; pollen ellipsoid. Fruits divaricate-ascending, not appressed to rachis, not secund, straight, edges parallel, 4-7.3 cm × 2.7-4 mm; valves glabrous; ovules 44-52 per ovary; style 0.05-0.1 mm. Seeds uniseriate, 1.9-2.3 mm in diam.; wing continuous, 0.3-0.5 mm wide.
Flowering Apr-May. Rocky slopes and gravelly soil in desert scrub and pinyon-juniper communities; 1500-2300 m; Calif., Nev.
Boechera dispar is a distinctive sexual diploid that is known from Inyo, Mono, and San Bernardino counties, California, and Nye County, Nevada.