Ceanothus cordulatus |
Ceanothus megacarpus |
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mountain whitethorn, snow bush, whitethorn ceanothus |
big pod ceanothus |
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Habit | 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. | Shrubs, 1.5–6 m. Stems erect to ascending, not rooting at nodes; branchlets grayish brown to brown, flexible, appressed puberulent to tomentulose, hairs straight. | ||||
Leaves | 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. |
sometimes alternate, not fascicled, sometimes crowded; petiole 1–5 mm; blade flat to cupped, oval, elliptic, or oblanceolate, 10–25(–33) × 5–19 mm, base cuneate to rounded, margins thick, usually entire, rarely remotely denticulate, teeth 5–7, apex obtuse, abaxial surface pale green, glabrous or sparsely strigillose on veins, adaxial surface green, glabrous. |
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Inflorescences | axillary, umbel-like or racemelike, sometimes densely clustered, 1.2–2(–4) cm. |
axillary, 1–2 cm. |
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Flowers | sepals, petals, and nectary usually white, rarely pink. |
sepals and petals white; nectary blue to black. |
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Capsules | 3.5–5 mm wide, lobed; valves rugose, viscid when young, weakly crested. |
7–12 mm wide, not lobed; valves smooth or rugulose to weakly ridged near apex; horns subapical, prominent, erect, often rugulose, or weakly developed to absent, intermediate ridges absent. |
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2n | = 24. |
= 24. |
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Ceanothus cordulatus |
Ceanothus megacarpus |
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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; NV; OR; Mexico (Baja California)
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CA
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Discussion | 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.) |
Varieties 2 (2 in the flora). Some populations of Ceanothus megacarpus are polymorphic for leaf arrangement. Plants assignable to either var. insularis or var. megacarpus based on leaf arrangement may have fruits intermediate to both varieties. Putative hybrids between var. megacarpus and C. cuneatus were reported by H. McMinn (1944), but their variable leaf arrangement (alternate and opposite on the same plant) may also represent intermediates between var. insularis and var. megacarpus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 87. | FNA vol. 12, p. 97. | ||||
Parent taxa | Rhamnaceae > Ceanothus > subg. Ceanothus | Rhamnaceae > Ceanothus > subg. Cerastes | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | C. macrocarpus | |||||
Name authority | Kellogg: Proc. Calif. Acad. Sci. 2: 124, fig. 39. (1863) | Nuttall: N. Amer. Sylv. 2: 46. (1846) | ||||
Web links |