New combinations and typifications in Vitex (Lamiaceae) from Madagascar

The genus Vitex L. (Lamiaceae) is pantropical and comprises c. 250 species, of which 42 are currently accepted for Madagascar, all endemic to the country, but one. A number of the Malagasy species of Vitex have been treated as comprising infraspecific taxa, including Vitex betsiliensis Humbert and Vitex cauliflora Moldenke (two subspecies and three varieties respectively), which are the subject of this note. We have undertaken a thorough review all of the available specimens in the herbaria at G, MO and P to gain a better understanding of the morphological variations of both species, and we conclude that the five intraspecific taxa each represent distinct species. We therefore provide the necessary new combinations: Vitex barorum (Humbert) Callm. & Phillipson and Vitex villossisima (Moldenke) Callm. & Phillipson, and the new name: Vitex humblotiana Callm. & Phillipson. Each of the five species is provided with notes on their morphological affinities and with risk of extinction assessments following the IUCN Red List Categories and Criteria.