Ceanothus oliganthus var. oliganthus
Stems: branchlets ± flexible, puberulent to villosulous. Leaf-blades ovate, elliptic, or elliptic-oblong, adaxial surface usually villosulous, sometimes glabrate. Flowers: sepals, petals, and nectary blue or purplish blue; nectary and ovary glabrous. Capsules glabrous; valves smooth, usually crested, sometimes not.
Phenology: Flowering Mar–Jun.
Habitat: Open slopes and ridges, chaparral, woodlands.
Elevation: 60–1500 m.
Variety oliganthus occurs primarily in the Coast Ranges south of San Francisco Bay, the Transverse Ranges, and the northern Peninsular Ranges. Putative hybrids and intergradation with var. orcuttii and Ceanothus tomentosus var. olivaceus have been reported from the Santa Ana Mountains, California (M. Van Rensselaer and H. McMinn 1942).
"thin" is not a number.