Stems usually branching, 1-6 dm. Leaves: basal persistent, 1-7 dm; blade lanceolate, flat. Inflorescences 2-several-flowered. Flowers erect; perianth open, campanulate; petals light yellow-green, flecked and streaked purplish brown, oblanceolate, ciliate to near apex, hairy; glands depressed, bordered proximally by ciliate membrane, distally by 2 or more rows of short hairs; anthers short-tipped. Capsules erect, angled, apex acute. Seeds dark brown, irregular. 2n = 20. Flowering late spring--early summer. Serpentine grasslands; of conservation concern; 0--200 m; Calif. Calochortus tiburonensis is known only from Ring Mountain, Marin County.