Confirmed polyphyly, generic recircumscription and typification of Dysoxylum (Meliaceae), with revised disposition of currently accepted species

Abstract

The hypothesis that Dysoxylum (Meliaceae), as currently circumscribed, is polyphyletic is tested. Analyses based on nuclear ribosomal ITS, ETS, the plastid trnL-trnF intron and intergenic spacer, as well as the rps15-ycf1 intergenic spacer support this hypothesis. Six strongly supported clades within Dysoxylum s.l. were recovered, in large part supporting the classification of Harms. Based on the largest molecular phylogenetic tree hitherto assembled, and morphological considerations, a revised disposition of 94 currently recognized Dysoxylum species, is presented, reinstating the genera Didymocheton, Epicharis, Goniocheton, Prasoxylon and Pseudocarapa. The first valid publication of the generic name Dysoxylum is identified, and it is typified with D. macrocarpum. Forty-three new combinations at species level and two at infraspecific are proposed; Didymocheton nutans, Dysoxylum alatum, D. pachyphyllum, Epicharis, Trichilia spectabilis and T. alliacea (second step) are lectotypified.