Herbage sparsely hairy. Stems erect to ascending. Flowers cup-shaped; sepals accrescent, oblong-lanceolate to lanceolate-ovate, 8.5-9 mm, abaxially glabrous or sparsely hairy, adaxially densely hairy; petals obovate, 4.5-8.5 mm, apex obtuse, not emarginate, sometimes erose; filaments 4.5-5 mm; anthers ca. 0.8 mm, usually dehiscing extrorsely; style 3.2-4 mm. Nutlets 3-5, tubercles broad-based, platelike cones.

Flowering Apr-May. Wet, inner edges of vernal pools; of conservation concern; 300-400 m; Oreg.

Subspecies grandiflora occurs primarily in the Agate Desert of Jackson County.