San Diego wirelettuce

Annuals, 50–200 cm. Stems single, branches ascending or spreading, glabrous. Leaves withered at flowering (glabrous). basal blades linear to oblanceolate, runcinate. 3–10 cm, margins pinnately lobed. cauline much reduced, bractlike . Heads borne singly or clustered along branches . Peduncles 3–4 mm. Calyculi of reflexed bractlets. Involucres 7–9 mm (sparsely glandular-puberulent). Florets 11–13. Cypselae light tan to brown, 1.9–2.3 mm, faces smooth, slightly bumpy or tuberculate, grooved; pappi of 19–21, white bristles (falling), plumose on distal 80–85%. 2n = 16.

Flowering Aug–Nov. Open, pioneer sites such as old clearings, sand dunes, coastal sage communities, chaparral openings, and sandy roadside embankments; 20–600 m; Calif.; Mexico (Baja California).

The morphologic characteristics of Stephanomeria diegensis are a combination of those of S. exigua and S. virgata, and the species is thought to have evolved from genetic segregates of their hybridization (L. D. Gottlieb 1971; G. P. Gallez and Gottlieb 1982).