A Taxonomic Revision of the Gymnosporia mossambicensis Group (Celastraceae: Celastroideae)

Abstract

The monophyletic Gymnosporia mossambicensis group occurs in eastern tropical and southern Africa, nearby Indian Ocean Islands and on Madagascar. Members are characterised, among other characters, by 3-locular capsules andseeds completely enveloped by an orange or bright yellow aril. Eleven species and four subspecies are recognised. Diagnostic characters to differentiate among species include growth form, hairiness of leaves, branches and peduncles, orientation of spines, presence and shape of stipules, colour of the flowers (white or red) and the shape of the capsules. Two species and one subspecies from Tanzania are newly described (G. livingstonei, G. schliebenii and (G. gracilis subsp. usambarensis). G. harveyana Loes. [previously considered conspecific with Maytenus mossambicensis (Klotzsch) Blakelock)] is reinstated as a distinct species. Maytenus mossambicensis var. stolzii N. Robson is treated as a subspecies of G. harveyana. G. bachmannii Loes., G. mossambicensis sensu stricto and G. nemorosa (Eckl. & Zeyh.) Szyszyl. retain their specific status in Gymnosporia. Maytenus drummondii N. Robson & Sebsebe, M. vanwykii R. H. Archer, M. mossambicensis var. gurueensis N. Robson and var. ruber (Harv.) Blakelock are transferred to Gymnosporia and the latter two varieties raised to species level. Maytenus mossambicensis var. ambonensis (Loes.) N. Robson is transferred to Gymnosporia and becomes G. gracilis Loes. subsp. gracilis. Two neotypes and two lectotypes are selected. A key to species and subspecies, distribution maps, and illustrations of all the taxa are provided.