Flora of North America species comparison

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Ceanothus impressus

Ceanothus arboreus

Santa Barbara ceanothus

feltleaf ceanothus, island ceanothus
Habit Shrubs, evergreen, 0.5–3 m. Stems erect, not rooting at nodes; branchlets brown, not thorn-tipped, round in cross section, flexible, puberulent. Shrubs, sometimes arborescent, evergreen, 2–7 m. Stems erect, not rooting at nodes; branchlets brown, not thorn-tipped, round or slightly angled in cross section, flexible, tomentulose.
Leaves

petiole 0–4 mm;

blade ± flat to strongly cupped, oblong, elliptic, or suborbiculate, 5–20(–25) × 2.5–17(–20) mm, base rounded, margins serrulate, thick to weakly or strongly revolute, teeth 11–29, apex obtuse to rounded, abaxial surface pale green, villosulous, adaxial surface dark to medium green, sparsely puberulent, not glandular papillate; pinnately veined, veins furrowed.

petiole 8–25 mm;

blade not aromatic, flat to cupped, widely ovate to elliptic, 25–80 × 20–40 mm, herbaceous, not resinous, base rounded, margins serrulate, teeth (35–)40–65, apex acute to obtuse, abaxial surface pale green, usually densely tomentulose, rarely glabrate, adaxial surface green, dull, glabrous or sparsely puberulent; 3-veined from base.
Inflorescences

axillary or terminal, umbel-like to racemelike, 1.2–3.5 cm.

axillary or terminal, paniclelike, conic, 5–12 cm.
Flowers

sepals, petals, and nectary blue.

sepals and petals pale blue to blue;

nectary blue to dark blue.
Capsules

3–4 mm wide, lobed;

valves smooth, crested.

6–8 mm wide, ± lobed;

valves rugose, ± viscid, weakly crested.
2n

= 24.

Ceanothus impressus

Ceanothus arboreus
Phenology Flowering Feb–May.
Habitat Rocky slopes, ridges, chaparral, oak woodlands, closed-cone pine woodlands.
Elevation 60–600 m. (200–2000 ft.)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Ceanothus arboreus is restricted to Santa Catalina, Santa Cruz, and Santa Rosa islands, California, and Guadalupe Island, Baja California. Plants with glabrate leaves on Santa Cruz and Santa Rosa Islands have been called C. arboreus var. glaber.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Leaf blades oblong to elliptic, 5–11(–14) × 2.5–8(–12) mm, strongly cupped, margins strongly revolute.
var. impressus
1. Leaf blades widely elliptic to suborbiculate, 11–20(–25) × 7–17(–20) mm, ± flat to cupped, margins thick to weakly revolute.
var. nipomensis
Source FNA vol. 12, p. 91. FNA vol. 12, p. 88.
Parent taxa Rhamnaceae > Ceanothus > subg. Ceanothus 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. 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. 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. 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
Subordinate taxa
C. impressus var. impressus, C. impressus var. nipomensis
Synonyms C. arboreus var. glaber
Name authority Trelease: Proc. Calif. Acad. Sci., ser. 2, 1: 112. (1888) Greene: Bull. Calif. Acad. Sci. 2: 144. (1886)
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).



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