Ceanothus cordulatus
Ceanothus diversifolius
mountain whitethorn, snow bush, whitethorn ceanothus
pine mat
spreading, sometimes rooting at nodes;
branchlets green, sometimes tinged red, not thorn-tipped, usually round, sometimes angled, in cross section, flexible, puberulent.
petiole 2–8 mm;
blade flat to cupped, ovate to elliptic, 10–30 × 6–18 mm, base rounded, margins usually entire, sometimes minutely glandular-denticulate distally, glands 18–30, apex obtuse, abaxial surface pale grayish green, sparsely puberulent or glabrous, sometimes villosulous along veins, adaxial surface pale green to grayish green, glaucous, dull, glabrate; 3-veined from base.
petiole 3–11 mm;
blade flat, elliptic to widely ovate, 12–45 × 6–20 mm, base obtuse to rounded, margins serrulate to denticulate, not revolute, usually not wavy, sometimes wavy, teeth 27–42, apex ± obtuse to rounded, abaxial surface pale green, pilosulous, adaxial surface green, pilosulous; usually pinnately veined, rarely 3-veined from base.
axillary, umbel-like or racemelike, sometimes densely clustered, 1.2–2(–4) cm.
axillary, umbel-like to racemelike, 1.3–4 cm.
sepals, petals, and nectary usually white, rarely pink.
sepals, petals, and nectary usually blue to pale blue, rarely white.
3.5–5 mm wide, lobed;
valves rugose, viscid when young, weakly crested.
4–5 mm wide, weakly lobed near apex;
valves smooth, crested.
= 24.
Ceanothus cordulatus
Ceanothus diversifolius
Ceanothus cordulatus is one of the most common shrubs in montane chaparral and forests of the Coast Ranges and Cascades of southern Oregon and northern California, southward through the Sierra Nevada, Transverse and Peninsular ranges of California, to the mountains of northern Baja California, and occurs disjunctly in the Charleston Mountains of Nevada.
Putative hybrids between Ceanothus cordulatus and C. velutinus var. velutinus, reported from the Klamath Mountains, the southern Cascade Range, and the Sierra Nevada, have been called C. ×lorenzenii (Jepson) McMinn. A rare intersectional hybrid between C. cordulatus and C. prostratus in the Lake Tahoe basin has been named C. ×serrulatus McMinn. Putative hybrids of C. cordulatus with C. diversifolius and C. integerrimus also have been reported (H. McMinn 1944).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Ceanothus diversifolius occurs in the North Coast Ranges and the western slopes of the Cascade Range and the Sierra Nevada; it often forms mats to two meters wide. Marginal teeth on young leaves are notable in having more or less persistent, narrowly conic glands, not seen elsewhere in Ceanothus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
