16. Ceanothus oliganthus Nuttall in J. Torrey and A. Gray, Fl. N. Amer. 1: 266. 1838.
Shrubs, sometimes arborescent, evergreen, 2–3(–6) m. Stems erect, not rooting at nodes; branchlets reddish brown or brown, usually not, sometimes weakly, thorn-tipped, usually round, sometimes ± angled in cross section, flexible to rigid, glabrous, puberulent, or villosulous. Leaves: petiole 3–8 mm; blade flat, ovate to widely elliptic, 8–35 × 4–25 mm, base obtuse to subcordate, margins denticulate most of length, not revolute, teeth 19–71, apex obtuse, rounded, or acute, abaxial surface usually pale green, sometimes gray-green, sometimes glaucous, glabrate to hirtellous, adaxial surface dark green, villosulous, especially on the veins, or glabrate; 3-veined from base. Inflorescences axillary, racemelike, 1.5–5.2 cm. Flowers: sepals, petals, and nectary usually pale to deep blue or purplish blue, rarely white. Capsules 4–7 mm wide, lobed, ± depressed at apex; valves smooth or rugose, viscid, crested or not.
Varieties 3 (3 in the flora): California, nw Mexico.
M. Van Rensselaer and H. McMinn (1942) treated var. oliganthus and var. sorediatus as species, although they and R. F. Hoover (1970) discussed intergradation between the two forms throughout part of their distribution, especially in the southern Coast Ranges and Transverse Ranges of California.