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(Last Modified On 5/8/2013)
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(Last Modified On 5/8/2013)
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Genus
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Rhamnus L.
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PlaceOfPublication
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Sp. PI. 193. 1753.
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Description
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Trees or shrubs, rarely woody vines, mostly unarmed, deciduous, the buds scaly or naked. Leaves alternate, rarely opposite, pinnately-veined, entire or toothed, mostly petiolate. Inflorescences umbellate cymes, sometimes reduced to a single flower, sessile or pedunculate. Flowers bisexual or polygamo- dioecious, small, perigynous; floral tube cupulate to campanulate; calyx lobes 4-5, ovate to deltoid, deciduous separately or with the circumscissile upper part of the floral tube after anthesis; petals 4-5, shorter than the calyx-lobes, ovate to obovate, concave, hooded or flat, often clawed, the margin entire or bibbed apically, inserted at the margin of the floral tube; stamens 4-5, functional or sterile and rudimentary in carpellate flowers, about as long or longer than the petals, inserted at the upper margin of the floral tube; nectariferous disc lining the wall of the floral tube, sometimes thickened near its margin; ovary superior, 2-3-carpellate, + 2-3-locular, the ovules 2-3, the style simple or 2-3-lobed, the stigma 2-3-lobed. Fruit a drupe, subglobose, dark red to black, containing 2-3 pyrenes; seeds 2-3, lenticular or wedge-shaped.
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Habit
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Trees or shrubs, rarely woody vines
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Distribution
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A genus of about 150 species in the temperate and tropical regions of both hemispheres, but most abundant in eastern Asia and southwestern North America.
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Reference
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Wolf, C. B. The North American Species of Rhamnus. Rancho Santa Ana Bot. Gard. Monogr., Bot. Ser. 1. 136 pp. 1938.
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Key
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a. Umbels with a distinct peduncle ca. 1-2 cm long; leaves serrate ..... 1. R. pubescens aa. Umbels sessile; leaves entire ..... 2. R. capraeafolia
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