3. Smelowskia johnsonii G. A. Mulligan, Canad. Field-Naturalist. 115: 341. 2001.
Plants densely white-canescent throughout; caudex simple. Stems: several from base, unbranched or branched proximally, 0.4-1.6 dm, trichomes simple, 1-1.5 mm, mixed with smaller, dendritic ones. Basal leaves: petiole 0.8-1.3 cm, ciliate, trichomes simple; blade oblanceolate to spatulate, 0.8-1.8 cm × 3-7 mm, (terminal segments 0.2-0.7 cm × 1-4 mm), margins usually entire or apically 3-toothed or -lobed, rarely palmately 3-lobed, (terminal segments linear to ovate), apex obtuse (surfaces densely villous, silvery, trichomes primarily simple, 1-1.8 mm). Cauline leaves subsessile; blade similar to basal, smaller distally, margins entire. Racemes elongated in fruit. Fruiting pedicels ascending, (often forming less than 40˚ angle, straight), proximalmost bracteate, 11-27 mm, pubescent, trichomes primarily simple (to 1.5 mm). Flowers: sepals 3-3.5 mm; petals lavender to purplish, suborbicular to obovate, 4-5 × 3-4 mm, narrowed to claw, ca. 2 mm, apex rounded; anthers oblong, 0.5-0.7 mm. Fruits ascending, ellipsoid to obovoid-ellipsoid, subterete, 5-6 × 2-3 mm, base and sometimes apex cuneate; valves each with obscure midvein; ovules 4 per ovary; style 0.2-0.3 mm. Seeds 2.2-2.7 × ca. 1 mm.
Flowering Jun-Aug. Steep talus slopes, loose rocks, limestone rubble, talus; of conservation concern; 0-600 m; Alaska.
Smelowskia johnsonii is known only from the Bering Strait District, Alaska. It is a distinctive species resembling only superficially the villous forms of S. borealis with simple trichomes. From the latter, S. johnsonii is easily distinguished by having subterete (versus angustiseptate) fruits 2-3 (versus 4-8) mm wide, non-secund (versus secund) and straight (versus often curved) fruiting pedicels, 4 (versus 10-18) ovules per ovary, and simple or apically 3 (or 5)-toothed or -lobed (versus palmately (3 or) 5 (or 7)-lobed) basal leaf blades. It is readily distinguished from all species of the genus by having leaves densely silvery pubescent, with primarily simple trichomes 1-1.8 mm.