Boechera rectissima

Biennials or perennials; short-lived; sexual; caudex present or absent. Stems usually 1 per caudex branch, arising from center of rosette near ground surface, 2-8(-10) dm, usually glabrous proximally, rarely sparsely pubescent, trichomes simple, to 0.7 mm, glabrous distally. Basal leaves: blade oblanceolate, 3-8(-13) mm wide, margins entire or denticulate, ciliate, trichomes (simple), 0.5-1.2 mm, surfaces sparsely to densely pubescent, trichomes simple, to 0.8 mm, often mixed with short-stalked, 2- or 3-rayed ones, 0.15-0.5 mm. Cauline leaves: 6-30(-45), often concealing stem proximally; blade auricles 1-1.5 mm, surfaces of distalmost leaves sparsely pubescent, sometimes margins ciliate. Racemes 10-30(-50) -flowered, usually unbranched. Fruiting pedicels reflexed, abruptly recurved at base, otherwise straight, 4-10 mm, glabrous. Flowers pendent at anthesis; sepals pubescent; petals white, 3-4 × 0.7-1.2 mm, glabrous; pollen ellipsoid. Fruits strongly reflexed, usually appressed to rachis, not secund, straight, edges parallel, 5-9 cm × 1.8-2.5 mm; valves glabrous; ovules 46-80 per ovary; style 0.2-0.8 mm. Seeds uniseriate, 1.8-2.1 × 1-1.5 mm; wing continuous, 0.15-0.25 mm wide.

Flowering May-Jul. Rocky slopes in open conifer forests; 1500-2500 m; Calif., Oreg.

Boechera rectissima is easily recognized by its combination of glabrous stems, basal leaves with large, predominantly simple trichomes, short (3-4 mm), white petals, and strongly reflexed, appressed fruits. Plants assigned to var. simulans appear to be hybrids between this species and B. retrofracta.