Taxonomic revision of Phyllanthus (Phyllanthaceae) in Madagascar and the Comoro Islands I: synopsis and subgenera Isocladus, Betsileani, Kirganelia and Tenellanthus

In this first part of a taxonomic revision of Phyllanthus L. in Madagascar and the Comoro Islands, a synopsis of the 55 species and a key to the nine subgenera (three of which are new) and two sections are given. The taxonomic treatment in this paper includes the 11 species, four subspecies and two varieties of subgenera Isocladus G. L. Webster, Betsileani (Jean F. Brunel) Ralim. & Petra Hoffm. stat. nov., Kirganelia (A. Juss.) G. L. Webster and Tenellanthus Jean F. Brunel. Distribution maps and IUCN conservation assessments are provided for each taxon. The three Madagascan endemic species without phyllanthoid branching are placed in the new subgen. Betsileani separate from subgen. Isocladus. Revised circumscription of species within Kirganelia s.s. reduces the number of species in this group from nine to four. Section Pentandra G. L. Webster is separated as subgen. Tenellanthus as suggested by Brunel (1987).