Shrubs, sometimes arborescent, evergreen, 2–6 m. Stems erect, not rooting at nodes; branchlets green, thorn-tipped or not, round to ± angled in cross-section, rigid, glabrous or sparsely puberulent. Leaves: not fascicled; petiole 4–7 mm; blade ± cupped, elliptic to oblong, 11–35 × 8–29 mm, base cuneate to rounded, margins entire, apex obtuse to weakly retuse, abaxial surface pale green, not glaucous, sometimes puberulent on midribs, adaxial surface green, shiny, glabrous; pinnately veined. Inflorescences axillary, paniclelike, 4–17 cm. Flowers: sepals, petals, and nectary pale blue to blue. Capsules 4–6 mm wide, not lobed; valves smooth, not conspicuously viscid, not or weakly crested. 2n = 24.

Phenology: Flowering Jan–May.
Habitat: Rocky slopes, coastal sage scrub, chaparral.
Elevation: 60–900 m.

Distribution

• Generated Map
• Legacy Map

Calif., Mexico (Baja California)

Discussion

Like Ceanothus incanus, plants of C. spinosus are polymorphic for the presence of thorn-tipped branchlets. Putative hybrids with C. thyrsiflorus and C. oliganthus var. sorediatus have been reported (M. Van Rensselaer and H. McMinn 1944).

Selected References

None.

Lower Taxa

None.

"thin" is not a number.