Ceanothus cuneatus |
Ceanothus cordulatus |
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buck brush, common buckbrush, narrow-leaf buckthorn, sedge-leaf buckthorn, wedgeleaf cuneatus |
mountain whitethorn, snow bush, whitethorn ceanothus |
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Habit | Shrubs, 0.5–3.5 m. Stems erect, ascending, or spreading, not rooting at nodes; branchlets grayish brown to brown, rigid or flexible, glabrate, puberulent, or tomentulose, hairs straight. | Shrubs, evergreen, 0.5–1.5 m. Stems ascending to spreading, not rooting at nodes; branchlets yellowish or grayish green, glaucescent, thorn-tipped, round in cross section, rigid, puberulent, glabrescent. | ||||||||||||
Leaves | usually both fascicled and not fascicled on same plant, rarely none fascicled; petiole 1–3 mm; blade flat to cupped, elliptic, oblanceolate, obovate, or orbiculate, 4–22(–30) × 3–12(–22) mm, base rounded, margins thick, not revolute, entire or denticulate distal to middle, teeth 0–9, apex obtuse, rounded, truncate, or retuse, abaxial surface pale green, glabrate or glabrous, adaxial surface green, glabrous. |
petiole 2–8 mm; blade flat to cupped, ovate to elliptic, 10–30 × 6–18 mm, base rounded, margins usually entire, sometimes minutely glandular-denticulate distally, glands 18–30, apex obtuse, abaxial surface pale grayish green, sparsely puberulent or glabrous, sometimes villosulous along veins, adaxial surface pale green to grayish green, glaucous, dull, glabrate; 3-veined from base. |
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Inflorescences | axillary or terminal, 0.8–2.5 cm. |
axillary, umbel-like or racemelike, sometimes densely clustered, 1.2–2(–4) cm. |
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Flowers | sepals, petals, and nectary white to lavender or blue. |
sepals, petals, and nectary usually white, rarely pink. |
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Capsules | 4–6 mm wide, weakly lobed; valves smooth, horns subapical, prominent, erect, intermediate ridges absent. |
3.5–5 mm wide, lobed; valves rugose, viscid when young, weakly crested. |
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2n | = 24. |
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Ceanothus cuneatus |
Ceanothus cordulatus |
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Phenology | Flowering May–Jul. | |||||||||||||
Habitat | Rocky ridges and slopes, chaparral, conifer and mixed evergreen forests. | |||||||||||||
Elevation | 400–3400 m. (1300–11200 ft.) | |||||||||||||
Distribution |
CA; OR; nw Mexico
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CA; NV; OR; Mexico (Baja California)
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Discussion | Varieties 4 (4 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Ceanothus cordulatus is one of the most common shrubs in montane chaparral and forests of the Coast Ranges and Cascades of southern Oregon and northern California, southward through the Sierra Nevada, Transverse and Peninsular ranges of California, to the mountains of northern Baja California, and occurs disjunctly in the Charleston Mountains of Nevada. Putative hybrids between Ceanothus cordulatus and C. velutinus var. velutinus, reported from the Klamath Mountains, the southern Cascade Range, and the Sierra Nevada, have been called C. ×lorenzenii (Jepson) McMinn. A rare intersectional hybrid between C. cordulatus and C. prostratus in the Lake Tahoe basin has been named C. ×serrulatus McMinn. Putative hybrids of C. cordulatus with C. diversifolius and C. integerrimus also have been reported (H. McMinn 1944). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 99. | FNA vol. 12, p. 87. | ||||||||||||
Parent taxa | Rhamnaceae > Ceanothus > subg. Cerastes | Rhamnaceae > Ceanothus > subg. Ceanothus | ||||||||||||
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Subordinate taxa | ||||||||||||||
Synonyms | Rhamnus cuneata | |||||||||||||
Name authority | (Hooker) Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 267. (1838) | Kellogg: Proc. Calif. Acad. Sci. 2: 124, fig. 39. (1863) | ||||||||||||
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