Boechera rollei

Perennials; long-lived; sexual; caudex woody. Stems usually 1 per caudex branch, arising from center of rosette, elevated above ground surface on woody base, 1.5-2.5 dm, glabrous throughout. Basal leaves: blade oblanceolate, 3-8 mm wide, margins entire, ciliate proximally, trichomes (simple), 0.2-0.7 mm, surfaces glabrous or sparsely pubescent, trichomes short-stalked, 2-4-rayed, 0.2-0.4 mm. Cauline leaves: 6-12, sometimes concealing stem proximally; blade auricles 0.5-2.5 mm, surfaces of distalmost leaves glabrous. Racemes 3-7 -flowered, unbranched. Fruiting pedicels strongly curved proximally, 4-6 mm, glabrous. Flowers divaricate-ascending at anthesis; sepals glabrous; petals creamy white, 8-11 × 2-2.5 mm, glabrous; pollen ellipsoid. Fruits pendent, not appressed to rachis, not secund, straight to slightly curved, edges undulate (not parallel), 3.5-6 cm × 2.5-3.5 mm; valves glabrous; ovules 14-22 per ovary; style 0.5-1 mm. Seeds uniseriate, 3-4 × 1.5-2 mm; wing distal and proximal, 0.3-0.6 mm wide.

Flowering Aug. Peridotite rocks on sparsely forested slopes; 1600-1800 m; Calif.

Boechera rollei is easily distinguished from the habitally similar B. suffrutescens by its longer (8-11 versus 4.5-6 mm) petals, narrower (2.5-3.5 versus 3-6 mm) fruits, and narrower (0.3-0.6 versus 0.8-1.5 mm) seed wings. This distinctive sexual species is known only from the vicinity of the type locality on the divide between the Applegate and Klamath Rivers in Siskiyou County.