Sur les Pandanus (Pandanaceae) à stigmates saillants de la côte est de Madagascar

Recent fieldwork and work in herbaria allow a better understanding of the family Pandanaceae in Madagascar. This article proposes a taxonomic treatment of the morphologically isolated Malagasy oriental species with sharp protuberant stigmas. A new species is described: Pandanus callmanderiana endemic to the littoral forests and swampy areas of the East-North-East of the Great Island. This species is characterized by a “coniferoid” habit, with one deltoid fertile stigma surrounded by numerous long spiniform and sterile stigmas. A key of Malagasy sections as well as a reflection on the systematics of Pandanaceae are presented. Pandanus ferox and P. pichi-sermollii are both synonyms of P. guillaumetii. The description of three monospecific sections, sect. Callmanderia, Guillaumetia and Insuetia, provides a morphologically convenient division of Malagasy Pandanus. These sections are typified respectively by P. callmanderiana, P. guillaumetii and P. insuetus.