Frangula rubra |
Frangula rubra subsp. obtusissima |
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red buckthorn, Sierra coffee berry |
obtuse buckthorn |
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Habit | Shrubs, 0.5–2 m. Stems red to gray, glabrous or 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. |
scattered along branchlets; blade light green abaxially, green or dull green adaxially, oblong to obovate, 2.5–6 cm, base rounded, margins entire or serrulate, apex rounded, abaxial surface glabrous or puberulent on midrib and veins, adaxial glabrous. |
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Inflorescences | umbels, pedunculate, (2–)4–15-flowered. |
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Pedicels | 1–12 mm. |
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Drupes | black, globose or pyriform, 8–12 mm; stones 2(–3). |
globose. |
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Stigmas | 2-lobed. |
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Young | branches usually red, rarely gray. |
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Frangula rubra |
Frangula rubra subsp. obtusissima |
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Phenology | Flowering Apr–Jun. | |||||||||||||||||
Habitat | Chaparral, montane forests. | |||||||||||||||||
Elevation | 800–2100 m. (2600–6900 ft.) | |||||||||||||||||
Distribution |
CA; NV; OR |
CA; NV |
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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.) |
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Key |
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Source | FNA vol. 12, p. 55. | FNA vol. 12, p. 56. | ||||||||||||||||
Parent taxa | Rhamnaceae > Frangula | Rhamnaceae > Frangula > Frangula rubra | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | Rhamnus rubra | Rhamnus obtusissima, R. rubra subsp. obtusissima | ||||||||||||||||
Name authority | (Greene) Grubov: Trudy Bot. Inst. Akad. Nauk S.S.S.R., Ser. 1, Fl. Sist. Vyssh. Rast. 8: 271. (1949) | (Greene) Kartesz & Gandhi: Phytologia 76: 449. (1994) | ||||||||||||||||
Web links |