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Bolinas ceanothus, Mason's ceanothus

Carmel ceanothus

Habit Shrubs, 0.6–2 m. Stems erect to ascending, not rooting at nodes; branchlets dark brown, rigid, ± tomentulose. Shrubs, sometimes arborescent, evergreen, 0.5–4 m. Stems erect, ascending to arcuate, rarely prostrate, not rooting at nodes; branchlets green, not thorn-tipped, angled in cross section, flexible, sparsely puberulent or glabrous.
Leaves

not fascicled;

petiole 1–2 mm;

blade flat, usually elliptic or oval, sometimes suborbiculate, 7–21 × 4–13 mm, base rounded to ± cuneate, margins not revolute, denticulate most of length, teeth 9–17, apex obtuse, rounded to truncate, abaxial surface pale green to grayish green, strigose on veins, glabrate, adaxial surface dark green, glabrous.

petiole 5–10 mm;

blade flat to cupped, ovate to suborbiculate, 10–45 × 10–30 mm, base obtuse to rounded, margins denticulate, ± revolute, teeth 21–45, apex obtuse to rounded, abaxial surface pale green, puberulent to densely villosulous, veins prominently raised, puberulent to villosulous, adaxial surface dark green, glabrate; 3-veined from base.

Inflorescences

axillary, 1–2.5 cm.

axillary, paniclelike, 2–7 cm.

Flowers

sepals, petals, and nectary deep blue to purple.

sepals, petals, and nectary blue.

Capsules

3–4 mm wide, not lobed;

valves smooth, horns apical, minute, not rugose, intermediate ridges absent.

3–4 mm wide, weakly lobed at apex;

valves smooth, viscid, not crested.

2n

= 24.

Ceanothus masonii

Ceanothus griseus

Phenology Flowering Feb–Apr. Flowering Mar–Jun.
Habitat Soils derived from serpentine, chaparral, pine forests. Sandy or rocky flats and slopes, maritime chaparral, open sites in pine and cypress forests.
Elevation 100–500 m. (300–1600 ft.) 10–200 m. (0–700 ft.)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
Discussion

Ceanothus masonii occurs only at a few localities on Bolinas Ridge, Marin County. With the exception of its leaf morphology, it bears a close resemblance to C. gloriosus var. exaltatus.

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

Ceanothus griseus is distributed along the coast from Mendocino County south to Santa Barbara County. Plants with incompletely revolute leaf margins and abaxial surfaces intermediate or similar to those of C. thyrsiflorus are encountered frequently. Whether this pattern is a result of primary or secondary intergradation is not known. Prostrate plants with wide elliptic leaves have been called C. griseus var. horizontalis McMinn; they retain their stature under cultivation. Putative hybrids with C. dentatus have been named C. ×lobbianus Hooker (M. Van Rensselaer and H. McMinn 1942). Ceanothus ×veitchianus Hooker is a rare intersubgeneric hybrid between C. griseus and C. rigidus, first collected by William Lobb near Monterey in 1853, that is cultivated in Great Britain as an ornamental.

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

Source FNA vol. 12, p. 103. FNA vol. 12, p. 91.
Parent taxa Rhamnaceae > Ceanothus > subg. Cerastes Rhamnaceae > Ceanothus > subg. Ceanothus
Sibling taxa
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. 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. 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
Synonyms C. thyrsiflorus var. griseus, C. griseus var. horizontalis
Name authority McMinn: Madroño 6: 171. (1942) (Trelease) McMinn: in M. van Rensselaer and H. McMinn, Ceanothus, 210. (1942)
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