A taxonomic revision of Madagascan Gardenia (Rubiaceae,Gardenieae)

A taxonomic revision of Madagascan Gardenia is presented, to include four species and two subspecies. Three species, Gardenia sambiranensis Rakoton. & A. P. Davis, G. manongarivenis Rakoton. & A. P. Davis, G. brevicalyx Rakoton. & A. P. Davis and one subspecies, G. rutenbergiana subsp. australis Rakoton. & A. P. Davis, are described as new to science. Identification keys, descriptions, distribution maps, illustrations, species notes (distribution, habitat and ecology, phenology), and conservation assessments are provided. Madagascan Gardenia species are restricted to western Madagascar, in seasonally dry and sub‐humid vegetation types. At least two species demonstrate broad ecological and anthropogenic tolerance, which may make them suitable for vegetation restoration projects in western Madagascar.