The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

mountain whitethorn, snow bush, whitethorn ceanothus

ladybush, Parry ceanothus, Parry's ceanothus

Habit Shrubs, evergreen, 0.5–1.5 m. Stems ascending to spreading, not rooting at nodes; branchlets yellowish or grayish green, glaucescent, thorn-tipped, round in cross section, rigid, puberulent, glabrescent. Shrubs, evergreen, 2–6 m. Stems erect or ascending, not rooting at nodes; branchlets grayish green to brown, not thorn-tipped, usually round, sometimes ± angled, in cross section, flexible, lanate to woolly, glabrescent.
Leaves

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 1–8 mm;

blade flat to slightly cupped, oblong or ± elliptic, 12–50 × 6–20 mm, base obtuse to rounded, margins entire or obscurely glandular-denticulate, narrowly revolute, glands 21–36, apex obtuse, abaxial surface green, cobwebby, soon glabrescent, adaxial surface dark green, shiny, villosulous, glabrescent; usually 3-veined from base, rarely pinnately veined.

Inflorescences

axillary, umbel-like or racemelike, sometimes densely clustered, 1.2–2(–4) cm.

axillary or terminal, paniclelike, 5–15 cm.

Flowers

sepals, petals, and nectary usually white, rarely pink.

sepals, petals, and nectary deep blue.

Capsules

3.5–5 mm wide, lobed;

valves rugose, viscid when young, weakly crested.

2.5–4 mm wide, lobed;

valves smooth, not or weakly crested.

2n

= 24.

= 24.

Ceanothus cordulatus

Ceanothus parryi

Phenology Flowering May–Jul. Flowering Apr–May.
Habitat Rocky ridges and slopes, chaparral, conifer and mixed evergreen forests. Rocky soils, open sites, flats, mixed evergreen and redwood forests.
Elevation 400–3400 m. (1300–11200 ft.) 30–800 m. (100–2600 ft.)
Distribution
from FNA
CA; NV; OR; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

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 parryi occurs in the outer coast ranges of Oregon (Benton and Lane counties) and from Humboldt County south to Napa County in California; it is reported to hybridize with C. foliosus, C. incanus, and C. thyrsiflorus (H. McMinn 1944). The deep blue sepals and petals, cobwebby indumentum on young leaves, and narrowly revolute leaf margins are diagnostic.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 12, p. 87. FNA vol. 12, p. 90.
Parent taxa Rhamnaceae > Ceanothus > subg. Ceanothus Rhamnaceae > Ceanothus > subg. Ceanothus
Sibling taxa
C. americanus, C. arboreus, C. arcuatus, C. confusus, C. crassifolius, C. cuneatus, C. cyaneus, C. dentatus, C. divergens, C. diversifolius, C. fendleri, C. ferrisiae, C. foliosus, C. fresnensis, C. gloriosus, C. griseus, C. hearstiorum, C. herbaceus, C. impressus, C. incanus, C. integerrimus, C. jepsonii, C. lemmonii, C. leucodermis, C. maritimus, C. martini, C. masonii, C. megacarpus, C. microphyllus, C. oliganthus, C. ophiochilus, C. otayensis, C. palmeri, C. papillosus, C. parryi, C. parvifolius, C. pauciflorus, C. perplexans, C. pinetorum, C. prostratus, C. pumilus, C. purpureus, C. roderickii, C. sanguineus, C. sonomensis, C. spinosus, C. thyrsiflorus, C. tomentosus, C. velutinus, C. verrucosus
C. americanus, C. arboreus, C. arcuatus, C. confusus, C. cordulatus, C. crassifolius, C. cuneatus, C. cyaneus, C. dentatus, C. divergens, C. diversifolius, C. fendleri, C. ferrisiae, C. foliosus, C. fresnensis, C. gloriosus, C. griseus, C. hearstiorum, C. herbaceus, C. impressus, C. incanus, C. integerrimus, C. jepsonii, C. lemmonii, C. leucodermis, C. maritimus, C. martini, C. masonii, C. megacarpus, C. microphyllus, C. oliganthus, C. ophiochilus, C. otayensis, C. palmeri, C. papillosus, C. parvifolius, C. pauciflorus, C. perplexans, C. pinetorum, C. prostratus, C. pumilus, C. purpureus, C. roderickii, C. sanguineus, C. sonomensis, C. spinosus, C. thyrsiflorus, C. tomentosus, C. velutinus, C. verrucosus
Name authority Kellogg: Proc. Calif. Acad. Sci. 2: 124, fig. 39. (1863) Trelease: Proc. Calif. Acad. Sci., ser. 2, 1: 109. (1888)
Web links