Syst. Bot. 14: 12, figs. 1, 2, 3f–j, 4, 5. 1989.
Stems not branching, straight, often scapelike, 2–3 dm, glabrous or glaucous. Leaves: basal solitary, clasping; blade narrowly lanceolate, hairy, adaxially hispid, abaxially glabrous, sometimes glaucous. Inflorescences 1–several-flowered; bracts 2, suboppo-site, narrowly lanceolate. Flowers erect; perianth open, campanulate; sepals lanceolate-acuminate, ca. 2 cm; petals white to cream, with dark purple-black, pentagonal to lunate blotch, broadly oblong to obovate, 3.5 cm, bearded, adaxial surface typically minutely papillose, margins erose; glands transversely oblong-lunate, slightly depressed, with 0.7–1.4 mm-wide band of short dendritic hairs distally, hairs surrounded by lime-green coloration and purple striations; anthers lanceolate, apex acuminate. Capsules nodding, 3–5.4 cm. Seeds 2.8–3.5 mm, with inflated bulbous crest and hollow lateral ridge. 2n = 20.
Phenology: Flowering late spring–mid summer.
Habitat: Grassland-forest ecotones in serpentine-derived soils
Elevation: 300–500 m
Of conservation concern.
Calochortus umpquaensis is known only from Watson and Ace Williams mountains on both sides of the Little River, Douglas County.