Convolvulus tridactylosus Eastwood, Proc. Calif. Acad. Sci., ser. 4, 20: 151. 1931

Stems to 50 cm, densely tomen­tose or ± villous, hairs brownish to grayish. Leaf blades notably 3-lobed, middle lobe oblong to broadly to narrowly triangular, lateral lobes usually antrorse, sometimes slightly retrorse or at right angles to middle lobe, margins not notably undulate, apex acute. Bracts lanceolate to linear-elliptic, 5–10 × 1.5–3.5 mm, apex acute. Flowers: sepals, at least outers, densely hairy, hairs appressed; corolla 27–33 mm.

Flowering May–Jun. Chaparral, woodlands; of conservation concern; 600–800 m; Calif.

Subspecies tridactylosa may be a result of introgression between Calystegia collina and C. occidentalis subsp. occidentalis.