Frangula rubra |
Frangula purshiana |
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red buckthorn, Sierra coffee berry |
bearberry, buckthorn, cascara, cascara buckthorn, cascara sagrada, false buckthorn |
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Habit | Shrubs, 0.5–2 m. Stems red to gray, glabrous or hairy. | Shrubs or trees, 1–12 m. Stems red to brown, gray, or green, glabrous or densely hairy. | ||||||||||||||||||||||||
Leaves | deciduous; petiole 2–12 mm; blade light to bright green abaxially, green or dull green adaxially, narrowly elliptic to oblong or obovate, 1.5–8.5 cm, ± herbaceous, base rounded to obtuse or acute, margins entire or serrulate to denticulate, apex acute to obtuse or rounded, surfaces glabrous or short-puberulent, or abaxial puberulent on midrib and veins; secondary veins (7–)8–11 pairs. |
deciduous or semideciduous, alternate; petiole 6–23 mm; blade usually pale green abaxially, green to bluish or greenish gray adaxially, not glaucous or glaucous when fresh, elliptic to oblong or oblong-obovate, (3.5–)5–15 cm, herbaceous or distinctly coriaceous, base rounded to subcordate, obtuse, or cuneate, margins entire, irregularly toothed, or serrulate, apex obtuse or truncate, both surfaces glabrous or sparsely to densely hairy, or adaxial velvety; secondary veins 9–11 pairs. |
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Inflorescences | umbels, pedunculate, (2–)4–15-flowered. |
umbels, pedunculate, 10–25-flowered. |
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Pedicels | 1–12 mm. |
5–15 mm. |
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Drupes | black, globose or pyriform, 8–12 mm; stones 2(–3). |
black, globose to depressed-globose, 5–10 mm; stones 3. |
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Stigmas | 2-lobed. |
2–3-lobed. |
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Frangula rubra |
Frangula purshiana |
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Distribution |
CA; NV; OR |
CA; ID; MT; OR; WA; BC
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Discussion | Subspecies 5 (5 in the flora). The Frangula rubra complex is a group of closely related populations that needs study. In Nevada, they occur only in Douglas and Washoe counties. Descriptions by C. B. Wolf (1938) provide only a single distinct character to separate the subspecies, and he reported much intergradations between subsp. obtusissima and all the other subspecies. Field and herbarium studies argue for the recognition of infraspecific taxa despite the intermediates. Subspecies yosemitana and Frangula californica subsp. cuspidata grow along the east side of the Sierra Nevada and can be easily confused. Plants of both taxa can be deciduous, but Wolf noted differences in pubescence and leaf margin to differentiate the two, although both are variable throughout their ranges. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 3 (3 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 55. | FNA vol. 12, p. 57. | ||||||||||||||||||||||||
Parent taxa | Rhamnaceae > Frangula | Rhamnaceae > Frangula | ||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||
Synonyms | Rhamnus rubra | Rhamnus purshiana | ||||||||||||||||||||||||
Name authority | (Greene) Grubov: Trudy Bot. Inst. Akad. Nauk S.S.S.R., Ser. 1, Fl. Sist. Vyssh. Rast. 8: 271. (1949) | (de Candolle) A. Gray ex J. G. Cooper: Trans. Amer. Med. Assoc. 10: 228. (1857) | ||||||||||||||||||||||||
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