Physaria eburniflora

Perennials; caudex usually simple; densely pubescent, trichomes (sessile), rays often furcate, fused toward base, (nearly smooth). Stems simple from base, prostrate, (arising lateral to rosette), 0.1-0.5 dm. Basal leaves: blade suborbicular, (1-)2.5(-3) cm, (base abruptly narrowed to petiole), margins entire, (flat), (surfaces densely silvery pubescent, trichomes in multiple layers, appressed). Cauline leaves (2-4); blade oblanceolate, ca. 1 cm, (base cuneate), margins entire, (apex acute). Racemes condensed. Fruiting pedicels (divaricate-ascending, nearly straight), 6-10 mm. Flowers: sepals (erect, purplish to greenish), linear-oblong or boat-shaped, 5.5-6.5 mm, (lateral pair more saccate than median); petals (white), spatulate, 9-12 mm, (claw undifferentiated from blade). Fruits strongly didymous, irregular in shape and size, (base slightly cordate, apex with a deep closed sinus), strongly to somewhat inflated, 6-8 × 6-8 mm (± bladderlike, papery); valves (retaining seeds after dehiscence), pubescent; replum elliptic to obovate, not constricted, as wide as or wider than fruit, apex obtuse; ovules 4-8 per ovary; style 4-5 mm, (sparsely pubescent or glabrous). Seeds plump.

Flowering May-Jun. Limestone hills, red soil, rocky calcareous slopes, clay depressions, granite and marble detritus; 1800-3000 m; Wyo.