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 thyrsiflorus

Ceanothus jepsonii

blue blossom, blue blossom ceanothus

Jepson ceanothus, Jepson's ceanothus, musk brush
Habit Shrubs, sometimes arborescent, evergreen, 0.5–6 m. Stems erect, usually ascending to arcuate, rarely prostrate, not rooting at nodes; branchlets green, not thorn-tipped, angled in cross section, flexible, not tuberculate, sparsely puberulent or glabrous. Shrubs, 0.5–1.5 m. Stems erect to ascending, not rooting at nodes; branchlets reddish to grayish brown, rigid, puberulent, glabrescent.
Leaves

petiole 3–10 mm;

blade flat to cupped, elliptic to ovate, 10–40(–50) × 5–15(–20) mm, base obtuse to rounded, margins denticulate to serrulate, usually not revolute, sometimes incompletely revolute, teeth glandular, 23–48, apex obtuse, abaxial surface pale green, sparsely puberulent to villosulous or glabrate, veins prominently raised, puberulent to villosulous, adaxial surface dark green, glabrate; 3-veined from base.

not fascicled, deflexed;

petiole 0–2 mm;

blade ± cupped, slightly folded lengthwise adaxially, elliptic to ± oblong, 10–20 × 5–13 mm, base rounded, margins thick or slightly revolute, spinose-dentate, teeth 7–11, apex rounded or sharply acute, abaxial surface pale yellowish green, glabrous, adaxial surface pale green, glabrous.
Inflorescences

terminal, usually racemelike, rarely paniclelike, 2.5–9 cm.

axillary or terminal, 1–2 cm.
Flowers

sepals, petals, and nectary usually pale to deep blue, rarely white.

sepals and petals (5–)6(–8), usually blue to lavender or white, rarely pink;

nectary blue;

stamens (5–)6(–8).
Capsules

3–4 mm wide, weakly lobed;

valves smooth, viscid, not crested.

5–7 mm wide, lobed;

valves rugose, horns subapical, prominent, thick, erect, rugose, intermediate ridges present.
2n

= 24.

Ceanothus thyrsiflorus

Ceanothus jepsonii
Phenology Flowering Mar–Jun.
Habitat Sandy or rocky flats and slopes, maritime chaparral, open sites in mixed evergreen and conifer forests.
Elevation 10–600 m. (0–2000 ft.)
Distribution
from FNA
CA; OR; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Ceanothus thyrsiflorus occurs along the coast from Coos County, Oregon, south to Santa Barbara County, California, and disjunctly near Eréndira, Baja California. A wide range of growth forms characterize this species and the closely related C. griseus, including plants ranging from almost prostrate to arborescent, sometimes with single trunks. Prostrate plants from several maritime bluffs along the California coast have been called C. thyrsiflorus var. repens McMinn; they retain their stature under cultivation. Named hybrids include C. ×regius (Jepson) McMinn (C. thyrsiflorus × C. papillosus) and C. ×vanrensselaeri Roof (C. thyrsiflorus × C. incanus). H. McMinn (1944) reported hybrids with C. foliosus.

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

Varieties 2 (2 in the flora).

Ceanothus jepsonii, composed of two, allopatric varieties, is the only species with mostly six (rarely eight) sepals and petals, and cymules reduced to solitary flowers (M. A. Nobs 1963). T. M. Hardig et al. (2000) provided evidence showing that the two varieties may not form a monophyletic group. H. McMinn (1942) and Nobs (1963) reported putative hybrids with C. cuneatus and C. prostratus.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Key
1. Sepals and petals usually pale blue to lavender, rarely pink or white; capsules globose.
var. jepsonii
1. Sepals and petals white; capsules ± oblong.
var. albiflorus
Source FNA vol. 12, p. 90. FNA vol. 12, p. 106.
Parent taxa Rhamnaceae > Ceanothus > subg. Ceanothus Rhamnaceae > Ceanothus > subg. Cerastes
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. 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. 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. 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. jepsonii var. albiflorus, C. jepsonii var. jepsonii
Synonyms C. thyrsiflorus var. chandleri, C. thyrsiflorus var. repens
Name authority Eschscholtz: Mém. Acad. Imp. Sci. St. Pétersbourg Hist. Acad. 10: 285. (1826) — (as thyrsiflora) Greene: Man. Bot. San Francisco, 78. (1894)
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 Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America, OregonFlora

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