The genus Syzygium (Myrtaceae) is revised for Indochina (Cambodia, Laos and Vietnam). The species key, descriptions, typification, ecology, conservation status, phenology, vernacular names, usages, distribution maps, selected herbarium images and list of specimens examined are given. A total of fifty-six species are recognised in Indochina. Eight species including Syzygium bokorense W.K.Soh & J.Parn., S. chantaranothaianum W.K.Soh & J.Parn., S. crassiflorum Merr. & L.M.Perry, S. cucphuongense W.K.Soh & J.Parn., S. glomerulatum (Gagnep.) Merr. & L.M.Perry, S. harmandii (Gagnep.) Merr. & L.M.Perry, S. pierrei (Gagnep.) Merr. & L.M.Perry and S. tonkinense (Gagnep.) Merr. & L.M.Perry are confined to Indochina. 63 lectotypes were designated and 23 previously accepted species names are now synonyms under Syzygium. Vietnam harbours the largest number of species (49), followed by Laos (30) and Cambodia (27). Syzygium attopeuense (Gagnep.) Merr. & L.M.Perry and Syzygium corticosum (Lour.) Merr. & L.M.Perry are new records for Thailand.

Trees in the genus Canarium L. are known to comprise an important component of the structure of Madagascar's moist forests, but recent work on Canarium in Madagascar reveals that the genus also comprises an important part of their diversity as well. To date, published Floras for Madagascar have recognized only three taxa of Canarium, but here we recognize 33 species, 27 of them new to science; this increases the number of accepted species in the genus by 33% worldwide and establishes Madagascar as a primary center of diversity for the genus. Despite its name, C. madagascariense Engl. proves to be one of the rarest and geographically most restricted species. Most Malagasy Canarium species are narrow endemic, and this is consistent with recent floristic and taxonomic research in other taxonomic groups on the island. The species of Canarium in Madagascar can be distinguished using mostly vegetative characters, and this will prove useful to foresters, ecologists, and conservationists. Most moist forests in Madagascar include multiple species of Canarium, and one important avenue of future research will be to further investigate the interdependence of the species of Canarium and the frugivorous lemurs that eat the pericarp of their fruits and possibly disperse their seeds.