Rhamnus

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. Species of subgenus Rhamnus have flowers with petals generally absent and the style exserted, whereas petals are absent and the style is included in subgenus Frangula (Hickman 1993).

Characters (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.

<==Rhamnus
    |--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

References

[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 10^th 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.