Flora of North America species comparison

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Ceanothus thyrsiflorus

Ceanothus leucodermis

blue blossom, blue blossom ceanothus

chaparral whitethorn
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, evergreen, 1.5–4 m. Stems erect, not rooting at nodes; branchlets light green or grayish green and glaucous, thorn-tipped, round in cross section, rigid, glabrous.
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.

petiole 3–7 mm;

blade flat, ovate to oblong-elliptic, 5–30 × 3–15 mm, base rounded to subcordate, margins usually entire to minutely glandular-serrulate, rarely serrate, glands 16–20, apex acute to obtuse, abaxial surface grayish green, glaucous, glabrous, adaxial surface green, ± glaucous, dull, usually glabrous, sometimes appressed villosulous; 3-veined from base.
Inflorescences

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

axillary, usually paniclelike, sometimes racemelike, (3–)5–15 cm.
Flowers

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

sepals, petals, and nectary white to blue.
Capsules

3–4 mm wide, weakly lobed;

valves smooth, viscid, not crested.

3–5 mm wide, lobed;

valves smooth, viscid, not crested.
2n

= 24.

= 24.

Ceanothus thyrsiflorus

Ceanothus leucodermis
Phenology Flowering Mar–Jun. Flowering Apr–Jun.
Habitat Sandy or rocky flats and slopes, maritime chaparral, open sites in mixed evergreen and conifer forests. Rocky slopes, chaparral, oak woodlands, conifer forests.
Elevation 10–600 m. (0–2000 ft.) 200–1800 m. (700–5900 ft.)
Distribution
from FNA
CA; OR; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; Mexico (Baja California)
[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.)

Ceanothus leucodermis is a common, often dominant species of chaparral in the mountains of central and southern California. This species is notable in producing serrate to serrulate leaves on stump sprouts following fire (M. Van Rensselaer and H. McMinn 1942). Putative hybrids and advanced generation intermediates with C. oliganthus occur throughout the southern Coast and Transverse ranges of California (McMinn 1944).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 90. FNA vol. 12, p. 86.
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. 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. jepsonii, C. lemmonii, 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. chandleri, C. thyrsiflorus var. repens
Name authority Eschscholtz: Mém. Acad. Imp. Sci. St. Pétersbourg Hist. Acad. 10: 285. (1826) — (as thyrsiflora) Greene: Bull. Misc. Inform. Kew 1895: 15. (1895)
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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