Plants usually bulbose; bulb coat membranous. Stems usually branching distally, ± flexuous, 2-6 dm. Leaves: basal withering, 1-3 dm; blade linear. Inflorescences 1-few-flowered; bracts opposite pedicel, 2-10 cm. Flowers erect; perianth open, broadly campanulate; sepals with purple blotch near base, lanceolate, 2-3 cm, apex acuminate; petals white tinged with lilac, with purple blotch near base, usually obovate, ± concave, 2-5 cm, glabrous except few hairs near base, apex obtuse; glands oblong, not depressed, densely hairy, hairs branching; filaments 8-10 mm; anthers lilac, oblong, 4-5 mm. Capsules erect, narrow-oblong, rounded in cross section, 2-5 cm, apex obtuse. Seeds light yellow, translucent, flat. 2n = 14. Flowering spring--early summer. Heavy soil, open grassy slopes, openings in brush; less than 700 m; Calif. Calochortus catalinae is increasingly threatened by habitat loss.