Sectional classification of Gymnosporia (Celastraceae), with notes on the nomenclatural and taxonomic history of the genus

Gymnosporia (Wight & Arn.) Hook. f. (Celastraceae) is an Old World genus of about 99 species and 19 infraspecific taxa. A historical review of the genus and its conserved status are given. Sectional subdivision of Gymnosporia into eight sections is based mainly on characters from fruit morphology and leaf anatomy. Taxonomically useful characters at section level include: presence or absence of leaf and fruit indumentum, number of valves in the fruit, aril colour and the degree to which it covers the seed. Diagnostic leaf anatomical characters are epidermis cell size, presence or absence of a hypodermis, uni- or multi-seriate epidermis, dorsiventral or isobilateral mesophyll and presence or absence of trichomes or papillae. The newly described sections (species/infraspecific taxa in brackets) are Buxifoliae (29); Capitatae (1); Gymnosporia (6/3); Mossambicenses (11/4); Vaccinifoliae (1/2); Pubescentes (1); Putterlickioides (1/2) and Tenuispinae (49/8). A key to the sections and a list of species in each section are provided. Morphological as well as leaf anatomical characters to assist in the identification of sections are tabulated. Eleven new name combinations, three new ranks and two new names are proposed.