in J. Torrey and A. Gray, Fl. N. Amer. 1: 584. 1840 (as parviflora) ,.
Plants slender. Flowering stems simple, 20–50 cm. Leaves in basal rosette and cauline, basal mostly 3-lobed, cauline (2–3), 3-foliolate, reduced, similar to basal (except lobes longer); stipules large, decurrent on petiole base, (margins fimbriate); petiole to 6 cm; blade dark green, orbiculate, (base cuneate), surfaces nearly glabrous or sparsely to densely hairy. Inflorescences 2–3, nodding, 4–14-flowered racemes, simple. Pedicels equaling or shorter than hypanthium. Flowers deciduous if unfertilized, not fragrant, horizontal; hypanthium obconic-elongate at anthesis, becoming very elongate in fruit, open at throat, (length 2 times diam.); sepals erect, triangular; petals (exserted), widely spreading, white or pink, often with prominent venation, obovate-rhombic, narrowly clawed, deeply 3-lobed, (usually with prominent sinuses extending 1/2+ to base), 7–16 mm, ultimate margins entire; ovary 1/2+ inferior; styles included in fruit; stigma papillae in narrow subapical band. Seeds 0.5–0.6 mm, wrinkled or smooth. 2n = 14, 21, 28, 35.
Phenology: Flowering Mar–Aug.
Habitat: Coastal bluffs, gravel prairies and rocky meadows, open forests, shrublands, and grasslands, subalpine regions, commonly with Lithophragma glabrum and L. tenellum
Elevation: 200-3100 m
Alta., B.C., Calif., Colo., Idaho, Mont., Nebr., Nev., Oreg., S.Dak., Utah, Wash., Wyo.
Lithophragma parviflorum is easily identified throughout its range, although morphological variation is apparent when comparing specimens from different habitats and elevations in western North America. Some authors treat L. trifoliatum as a variety of L. parviflorum.