Ceanothus prostratus var. occidentalis
Ceanothus, 262. 1942.
Shrubs, 0.1–0.3 m, matlike to moundlike. Stems prostrate, spreading, or ascending. Leaf-blades slightly folded lengthwise adaxially, margins ± wavy, teeth 5–9. Capsule horns spreading, not conspicuously rugose. 2n = 24.
Phenology: Flowering Apr–May.
Habitat: Gravelly or rocky soils derived from volcanic substrates, open flats and ridges, conifer forests.
Elevation: 800–1400 m.
Variety occidentalis is known from only a few localities in the mountains of Lake, Mendocino, Napa, and Sonoma counties. L. Abrams and R. S. Ferris (1923–1960, vol. 3) treated it as part of Ceanothus divergens, based partly on leaf morphology, but its life form and fruit morphology suggest a closer relationship to C. prostratus.
"thick" is not a number.