103. Boechera tiehmii (Rollins) Al-Shehbaz, Novon. 13: 389. 2003.
Arabis tiehmii Rollins, J. Arnold Arbor. 64: 496, fig. 2. 1983
Perennials; long-lived; sexual; caudex woody (covered by persistent leaf bases). Stems usually 2-5 per caudex branch, arising from margin of rosette near ground surface, 0.8-2 (-3) dm, glabrous throughout. Basal leaves: blade oblanceolate, (2-)3-7 mm wide, margins usually entire, rarely denticulate, ciliate, trichomes (simple and short-stalked) 2- or 3-rayed, 0.2-0.4 mm, surfaces glabrous. Cauline leaves: 3-5, not concealing stem; blade auricles absent or, rarely, to 0.5 mm, surfaces of distalmost leaves glabrous. Racemes 10-16-flowered, usually unbranched. Fruiting pedicels ascending, straight, 3-7 mm, glabrous. Flowers ascending at anthesis; sepals glabrous; petals white to lavender, 4-5 × 1.2-1.7 mm, glabrous; pollen ellipsoid. Fruits ascending, not appressed to rachis, not secund, straight, edges parallel, 1.5-3.7 cm × 1.4-1.7 mm; valves glabrous; ovules 14-22 per ovary; style 0.2-0.6 mm. Seeds uniseriate, 1.7-2.2 × 1-1.2 mm; wing absent or distal, 0-0.5 mm wide.
Flowering Jun-Aug. Rock outcrops and gravelly soils in alpine and subalpine habitats; of conservation concern; 3000-3500 m; Calif., Nev.
Boechera tiehmii is a sexual species considered by R. C. Rollins (1993) to be related to Arabis (Boechera) davidsonii. It is known only from Mono County, California, and Washoe County, Nevada.