Ceanothus cordulatus
Ceanothus integerrimus
mountain whitethorn, snow bush, whitethorn ceanothus
deer brush
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.
not fascicled;
petiole 3–12 mm;
blade flat, lanceolate, elliptic, oblong-elliptic, or ovate, (10–)20–80 × 10–45 mm, base rounded, margins entire or denticulate distally, teeth 3–5, apex acute to obtuse, abaxial surface pale green, glabrate or puberulent, especially on veins, sometimes glabrescent, adaxial surface green, dull, glabrous or sparsely puberulent; usually 3-veined from base, rarely pinnately veined.
axillary, umbel-like or racemelike, sometimes densely clustered, 1.2–2(–4) cm.
usually terminal, rarely axillary, racemelike or paniclelike, 5–25 cm.
sepals, petals, and nectary usually white, rarely pink.
sepals, petals, and nectary usually white or pale to dark blue, rarely pink.
3.5–5 mm wide, lobed;
valves rugose, viscid when young, weakly crested.
4–5 mm wide, lobed;
valves smooth, viscid, not or weakly crested.
= 24.
= 24.
Ceanothus cordulatus
Ceanothus integerrimus
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.)
G. T. Benson (1930) recognized four varieties in Ceanothus integerrimus, based on flower color, leaf blade shape, venation, and indumentum. With the exception of regional clines in indumentum density, N. C. Coile (1988) was unable to detect consistent patterns of variation correlated with ecological or geographical distribution. The types of C. integerrimus (D. Douglas in 1831) and C. andersonii (C. C. Parry in 1888) are notable in that they bear oblong leaf blades with one principal vein from the base; the basal pair of secondary veins are shorter than those distal to it and relatively short compared to those in leaves elsewhere in the species. This venation is restricted to only a few specimens from near Ben Lomond, Santa Cruz Mountains, California, and has not been seen since the collection by Parry. W. L. Jepson (1909–1943, vol. 2) suggested that the venation pattern may be correlated with the oblong leaf shape that is shown by the type specimens.
Young shoots of Ceanothus integerrimus were used by Native Americans in basketry and for arrow foreshafts (D. E. Moerman 1998).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
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