Chaparral broom, coyote brush, dwarf chaparral false willow

Shrubs, 15–450 cm (prostrate and mat-forming to erect and rounded, much branched). Stems spreading to ascending, dark brown, shiny, striate-angular, glabrous, often ± scurfy, usually resinous and sticky. Leaves present at flowering; sessile or short-petiolate; blades (1- or 3-nerved) oblanceolate to obovate, the smaller 5–40 × 2–15 mm (thick), bases cuneate, margins entire or coarsely dentate (teeth 3–9 distal to middles), faces glabrous, gland-dotted, resinous. Heads (100–200+) in (leafy) paniculiform arrays. Involucres hemispheric to campanulate; staminate 3.2–5 mm, pistillate 3–6 mm. Phyllaries ovate to lanceolate, 1–3 mm, margins yellowish, scarious, medians yellow proximally, green distally, apices obtuse to acute or acuminate (erose, abaxial faces papillose-scurfy). Staminate florets 20–34, 3–4 mm. Pistillate florets 19–43; corollas 2.5–3.5 mm. Cypselae 1–2 mm, 8–10-nerved, glabrous; pappi 6–9 mm.

Subspecies 2 (2 in the flora): w United States, nw Mexico.

Baccharis pilularis can be distinguished by its dark brown stems, and serrate, obovate to oblanceolate leaves. In addition, plants from some dunes of the California coast are prostrate, a growth form unique to this genus in our region.

The common, weedy, widespread form is subsp. consanguinea, which is typically erect, with its larger leaves 15–40 mm. Subspecies pilularis is known only from exposed sandy dunes and bluffs along the central coast of California. Its growth habit is matlike, and its larger leaves are 5–15 mm. The prostrate habit of subsp. pilularis is strikingly different from the upright habit of subsp. consanguinea.

SELECTED REFERENCE

Wolf, C. B. 1935. Observations on Baccharis pilularis DC. Occas. Pap. Rancho Santa Ana Bot. Gard. 1: 17–29.