Perennials; short- to long-lived; sexual; caudex usually not woody. Stems usually 2-6 per caudex branch, arising from margin of rosette near ground surface, 0.8-4 dm, densely pubescent proximally, trichomes simple and short-stalked, 2-rayed, 0.3-0.6 mm, glabrous distally. Basal leaves: blade narrowly oblanceolate, 1-5 mm wide, margins entire or few-toothed, ciliate proximally, trichomes (simple), to 0.9 mm, surfaces densely pubescent, trichomes simple and short-stalked, 2- or 3-rayed, 0.3-0.5 mm. Cauline leaves: 3-6, not concealing stem; blade auricles 0.3-0.6 mm, surfaces of distalmost leaves glabrous. Racemes 7-15-flowered, usually unbranched. Fruiting pedicels divaricate-ascending to horizontal, straight or gently recurved, 4-10 mm, glabrous or sparsely pubescent, trichomes spreading. Flowers ascending at anthesis; sepals pubescent; petals lavender, 3.5-6 × 1-1.5 mm, glabrous; pollen ellipsoid. Fruits divaricate-ascending to hori-zontal, not appressed to rachis, not secund, usually curved or straight, edges parallel, 2.5-4 cm × 1.2-1.5 mm; valves glabrous; ovules 50-80 per ovary; style 0.05-0.3 mm. Seeds uniseriate, 1-1.5 × 0.7-1 mm; wing usually distal, ca. 0.1 mm wide. Flowering May-Jun. Conglomerate and limestone outcrops in pinyon-juniper and mountain shrub-conifer communities; 2000-2600 m; Colo., Utah. Specimens of Boechera glareosa originally were identified as Arabis microphylla var. macounii (= B. macounii) by R. C. Rollins. The former (a sexual species) is distinguished from the latter (an apomictic hybrid) by having wider (1-2 versus 0.5-0.8 mm) petals, fewer (2-9 versus mostly 9-16) cauline leaves, and fewer (7-15 versus 10-33) flowers per inflorescence. Boechera glareosa is known only from Moffat County, Colorado, and Summit and Uintah counties, Utah.