Herbs, perennial, sometimes rhizomatous. Stems erect, (200–)300–950(–1250) mm, glandular-villous. Leaves basal and cauline, relatively even-sized; petiole absent; blade lanceolate to oblong-lanceolate or elliptic-lanceolate, 20–110(–130) × 5–33(–40) mm, margins dentate to serrate, plane or revolute, apex acute, surfaces finely pubescent-glandular. Pedicels 2–4(–7) mm in fruit. Flowers 2 per node, chasmogamous. Calyces not inflated in fruit, 20–35(–37) mm, densely glandular-pubescent, tube slightly dilated distally, lobes subequal, apex acute. Corollas bright golden yellow, often with reddish brown speckling on throat floor, palate ridges yellow, tube-throat 21–40 mm, limb 25–30 mm diam., nearly regular, lobes obovate-oblong. Anthers included, glabrous. Styles minutely glandular. Stigmas included, lobes unequal, abaxial 2 times longer than adaxial. Capsules 8–15(–17) mm. 2n = 20.
Phenology: Flowering Apr–Jun(–Jul).
Habitat: Dry, rocky openings in chaparral, roadcuts.
Elevation: 900–1500 m.
Calif., Mexico (Baja California).
Diplacus clevelandii is restricted to Orange, Riverside, and San Diego counties and in adjacent Mexico.