A molecular phylogeny of Aeridinae (Orchidaceae: Epidendroideae) inferred from multiple nuclear and chloroplast regions.

The subtribe Aeridinae, which contains approximately 90 genera, is one of the most diverse and taxonomically puzzling groups in Orchidaceae. In the present study, the phylogenetic relationships of Aeridinae were reconstructed utilizing five DNA sequences (ITS, atpI-H, matK, psbA-trnH, and trnL-F) from 211 taxa in 74 genera. The results of the phylogenetic analyses indicate that Aeridinae is monophyletic and that the subtribe can primarily be grouped into 10 clades: (1) Saccolabium clade, (2) Chiloschista clade, (3) Phalaenopsis clade, (4) Thrixspermum clade, (5) Vanda clade, (6) Aerides clade, (7) Trichoglottis clade, (8) Abdominea clade, (9) Gastrochilus clade, and (10) Cleisostoma clade. In our examination, most genera of Aeridinae were well-supported as monophyletic, and several genera, namely, Pteroceras, Cleisostoma, Vandopsis, Diploprora, Malleola, and Robiquetia, were found to be polyphyletic as currently circumscribed. In addition, several classifications of intra-genera, such as the subgenus Codonosepalum of Taeniophyllum and the section Gastrochilus of Gastrochilus, were also revealed to be paraphyletic. Due to the many questions raised by our phylogenies, the present study may serve as a reference for future taxonomic studies of Aeridinae.