An endangered new species of Podorungia (Acanthaceae), with notes on the tribe Barlerieae in Madagascar

摘要

The new species Podorungia gesnerioides Onjalalaina & I. Darbysh. is described and illustrated and its affinities to the other species in the genus are discussed. It is the only species in Podorungia with an open dichasial inflorescence. This new species is assessed as globally "Endangered" following the Categories and Criteria of IUCN, because of threats to its lowland forest habitat. The generic delimitation of the Malagasy genera in the tribe Barlerieae is discussed and the similarities of the five endemic genera to the tropical African genus Crabbea are noted. A key to the genera of Barlerieae in Madagascar is provided, based on the key in Benoist's Flore de Madagascar et des Comores account of the Acanthaceae. In addition, a brief review of current progress on the taxonomy of the Acanthaceae of Madagascar is provided.