Language: English with bilingual summary and keys in English and French
The Malagasy endemic genus Abrahamia Randrian. & Lowry (Anacardiaceae) is described and a taxonomic revision is presented in which 34 species are recognized, including 19 that are described as new. The previously known taxa from Madagascar have historically been treated in the genus Protorhus Engl. along with the type species from southern Africa, Protorhus longifolia (Bernh.) Engl. However, recent morphological and molecular phylogenetic studies have shown that the African species is more closely related to Ozoroa Delile and the Malagasy taxa comprise a distinct clade. Therefore the Malagasy taxa could no longer be accommodated in Protorhus, necessitating the description a new genus, described as Abrahamia. In the present revision, species of Abrahamia are recognized and distinguished from one another on the basis of morphological characters, primarily of the leaves, inﬂorescences, ﬂowers and fruits, in combination with eco-geographic features. A total of 15 new combinations are made for taxa from Madagascar previously placed in Protorhus, and lectotypes are designated for 11 names. A key to the species is provide in English and French, and a full description is presented for each species, along with a list of material examined and a distribution map; an illustration is also included for each of the new species. Preliminary conservation assessments following the IUCN Red List criteria indicate that 17 species, representing 50% of the total, are threatened, of which 5 are considered “Endangered” [EN] and 12 “Vulnerable” [VU].