Rhamnus

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.

<==Rhamnus
    |--R. sect. Rhamnus H93
    |    |--R. alnifolia H93
    |    |--R. crocea H93
    |    |--R. ilicifolia [=R. crocea ssp. ilicifolia] H93
    |    |--R. pilosa [=R. crocea ssp. pilosa] H93
    |    `--R. pirifolia [=R. crocea ssp. pirifolia] H93
    `--R. sect. Frangula H93
         |--‘Frangula’ alnus F05
         |--R. californica RJ11 [=Frangula californica SK93]
         |    |--R. c. var. californica H93
         |    `--R. c. var. occidentalis H93
         |--‘Frangula’ palmeri SK93
         |--‘Frangula’ polymorpha SK93
         |--R. purshiana H93 [=Frangula purshiana SK93; incl. R. purshiana var. annonifolia H93]
         |--R. rubra (see below for synonymy) H93
         |--‘Frangula’ sphaerosperma SK93
         `--R. tomentella H93
              |--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. alaternus SK93
  R. alpina SK93
  R. brandonensis CBH93
  R. carniolica SK93
  R. catharticus D01
  R. crenulata SK93
  R. fallax SK93
  R. frangula C55
  R. glandulosa SK93
  R. integrifolia SK93
  R. lanceolata SK93
  R. lojaconoi R-CT01
  R. myrtifolia SK93
  R. nepalensis BB07
  R. prinoides SK93
  R. pumila SK93
  R. saxatilis SK93
  R. sphaerosperma J87
  R. tinctoria SK93

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.

[F05] Fernández, J. 2005. Noticia de nuevos táxones para la ciencia en el ámbito Íbero-Balear y Macaronésico. Nuevos táxones animales descritos en la península Ibérica y Macaronesia desde 1994 (IX). Graellsia 61 (2): 261–282.

[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.

[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.