Flora of North America species comparison

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

Ceanothus cordulatus

Ceanothus hearstiorum

mountain whitethorn, snow bush, whitethorn ceanothus

Hearst ceanothus, Hearst ranch buckbrush, hearsts' ceanothus
Habit Shrubs, evergreen, 0.5–1.5 m. Shrubs, evergreen, 0.1–0.3 m, matlike or moundlike.
Stems

ascending to spreading, not rooting at nodes;

branchlets yellowish or grayish green, glaucescent, thorn-tipped, round in cross section, rigid, puberulent, glabrescent.

spreading or prostrate, not rooting at nodes, some flowering branches ascending;

branchlets green to reddish brown, not thorn-tipped, round or slightly angled in cross section, flexible, densely puberulent.
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 1–2 mm;

blade flat to cupped, linear, oblong, or oblong-obovate, 8–20 × 2–10 mm, base cuneate to obtuse, margins entire or obscurely glandular-denticulate, weakly revolute, glands 23–31, apex truncate or retuse, abaxial surface green, densely tomentulose, adaxial surface dark green, glandular-papillate and sometimes villosulous; pinnately veined, veins ± furrowed.
Inflorescences

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

terminal or axillary, umbel-like or racemelike, 1–5 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.

4–5 mm wide, not lobed to weakly lobed;

valves smooth, not crested.
2n

= 24.

Ceanothus cordulatus

Ceanothus hearstiorum
Phenology Flowering May–Jul. Flowering Mar–Apr.
Habitat Rocky ridges and slopes, chaparral, conifer and mixed evergreen forests. Consolidated alluvial or serpentine soils, maritime chaparral, coastal prairies.
Elevation 400–3400 m. [1300–11200 ft.] 20–200 m. [70–700 ft.]
Distribution
from FNA
CA; NV; OR; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[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 hearstiorum occurs in a small area of coastal bluffs in northern San Luis Obispo County, growing in close proximity to another local endemic, C. maritimus (subg. Cerastes).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 87. FNA vol. 12, p. 93.
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. 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
Name authority Kellogg: Proc. Calif. Acad. Sci. 2: 124, fig. 39. (1863) Hoover & Roof: Four Seasons 2(1): 4. (1966)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America, OregonFlora

The species comparison tool is brought to you by:
Northwest Wildflowers