Ceanothus thyrsiflorus |
Ceanothus cyaneus |
|
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blue blossom, blue blossom ceanothus |
lakeside ceanothus, San Diego buckbrush |
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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, 2–5 m. Stems erect, not rooting at nodes; branchlets light green, not thorn-tipped, angled in cross section, flexible, often tuberculate (tubercles minute, brownish), 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. |
petiole 2–6 mm; blade flat, ovate-elliptic, 20–50 × 15–20 mm, base rounded, margins usually denticulate to serrulate, rarely entire, not revolute, teeth 23–58, apex acute to obtuse, abaxial surface pale green, veins puberulent, adaxial surface dark green, glabrous or sparsely puberulent; 3-veined from base. |
Inflorescences | terminal, usually racemelike, rarely paniclelike, 2.5–9 cm. |
terminal, paniclelike, 15–30(–40) cm. |
Flowers | sepals, petals, and nectary usually pale to deep blue, rarely white. |
sepals, petals, and nectary deep blue. |
Capsules | 3–4 mm wide, weakly lobed; valves smooth, viscid, not crested. |
3–5 mm wide, deeply lobed; valves smooth, weakly crested. |
2n | = 24. |
= 24. |
Ceanothus thyrsiflorus |
Ceanothus cyaneus |
|
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 or gravelly slopes, chaparral. |
Elevation | 10–600 m. (0–2000 ft.) | 40–600 m. (100–2000 ft.) |
Distribution |
CA; OR; Mexico (Baja California)
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CA; Mexico (Baja California)
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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 cyaneus is known in the flora area only from San Diego County, and is threatened throughout its range. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 90. | FNA vol. 12, p. 90. |
Parent taxa | Rhamnaceae > Ceanothus > subg. Ceanothus | Rhamnaceae > Ceanothus > subg. Ceanothus |
Sibling taxa | ||
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) | Eastwood: Proc. Calif. Acad. Sci., ser. 4, 16: 361. (1927) |
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