California buckthorn Rhamnus californica, copyright Brofri.

Belongs within: Rhamnaceae.

Rhamnus, buckthorns, is a genus of shrubs and small trees found primarily in temperate regions with a smaller number of tropical species (Hickman 1993).

Characters (from Hickman 1993): Shrub, small tree. Stem with branches alternate, flexible; twigs sometimes thorn-tipped. Leaves sometimes clustered on short shoots, deciduous or evergreen, petioled; stipules deciduous; blade 1-ribbed from base, entire or not. Inflorescence and umbel or flowers solitary, axillary. Flowers bisexual or unisexual, gen >3 mm; hypanthium at base fused to, developing around ovary in fruit, above base deciduous; sepals 4 or 5; petals 0, 4, or 5; stamens 4 or 5; ovary appearing partly inferior, chambers 2-4, each 1-2-ovuled, style lobes 2-4. Fruit a drupe, 2-4-stoned.

|--R. sect. RhamnusH93
| |--R. alnifoliaH93
| |--R. croceaH93
| |--R. ilicifolia [=R. crocea ssp. ilicifolia]H93
| |--R. pilosa [=R. crocea ssp. pilosa]H93
| `--R. pirifolia [=R. crocea ssp. pirifolia]H93
`--R. sect. FrangulaH93
|--‘Frangula’ alnusSK93
|--R. californicaRJ11 [=Frangula californicaSK93]
| |--R. c. var. californicaH93
| `--R. c. var. occidentalisH93
|--‘Frangula’ palmeriSK93
|--‘Frangula’ polymorphaSK93
|--R. purshianaH93 [=Frangula purshianaSK93; incl. R. purshiana var. annonifoliaH93]
|--R. rubra (see below for synonymy)H93
|--‘Frangula’ sphaerospermaSK93
`--R. tomentellaH93
|--R. t. ssp. tomentella [=R. californica ssp. tomentella]H93
|--R. t. ssp. crassifolia [=R. californica ssp. crassifolia]H93
|--R. t. ssp. cuspidata [=R. californica ssp. cuspidata]H93
`--R. t. ssp. ursina [=R. californica ssp. ursina]H93

Rhamnus incertae sedis:
R. alaternusSK93
R. alpinaSK93
R. brandonensisCBH93
R. carniolicaSK93
R. catharticusD01
R. crenulataSK93
R. fallaxSK93
R. frangulaC55
R. glandulosaSK93
R. insulaM69
R. integrifoliaSK93
R. lanceolataSK93
R. lojaconoiR-CT01
R. myrtifoliaSK93
R. nepalensisBB07
R. prinoidesSK93
R. pumilaSK93
R. saxatilisSK93
R. sphaerospermaJ87
R. tinctoriaSK93

Rhamnus rubra [incl. R. rubra ssp. modocensis, R. rubra ssp. nevadensis, R. rubra ssp. obtusissima, R. rubra ssp. yosemitana]H93

*Type species of generic name indicated


[BB07] Baishya, A. K., & P. J. Bora. 2007. Cross community ethno-medico botany of Dibru-Saikhowa Biosphere Reserve, Assam. Bulletin of the Botanical Survey of India 49: 121–154.

[C55] Candolle, A. de. 1855. Géographie Botanique Raisonée: Ou exposition des faits principaux et des lois concernant la distribution géographique des plantes de l’époque actuelle vol. 1. Librairie de Victor Masson: Paris.

[CBH93] Collinson, M. E., M. C. Boulter & P. L. Holmes. 1993. Magnoliophyta (‘Angiospermae’). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 809–841. Chapman & Hall: London.

[D01] Doweld, A. B. 2001. The systematic relevance of fruit and seed structure in Bersama and Melianthus (Melianthaceae). Plant Systematics and Evolution 227: 75–103.

[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).

[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum—Biological Sciences 32 (1): 1–136.

[M69] Moran, R. 1969. Twelve new dicots from Baja California, Mexico. Transactions of the San Diego Society of Natural History 15 (17): 265–295.

[R-CT01] Ragusa-di Chiara, S., & H. Tsolakis. 2001. Phytoseiid faunas of natural and agricultural ecosystems in Sicily. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 522–529. CSIRO Publishing: Melbourne.

[RJ11] Rising, J. D., A. Jaramillo, J. L. Copete, P. G. Ryan & S. C. Madge. 2011. Family Emberizidae (buntings and New World sparrows). In: Hoyo, J. del, A. Elliott & D. A. Christie (eds) Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 428–683. Lynx Edicions: Barcelona.

[SK93] Schirarend, C., & E. Köhler. 1993. Rhamnaceae Juss. World Pollen and Spore Flora 17/18: 1–53.

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