Gastrochilus is an orchid genus containing 73 species of mainly epiphytic on trees or rocks in mountain forests of tropical and subtropical Asia. Previous phylogenetic analyses and morphological assessments have failed to produce a well-resolved phylogeny at the infrageneric level. In the present study, a new infrageneric classification of Gastrochilus is proposed based on thoroughly morphological and phylogenetic analyses based on 52 species. Our phylogenetic analysis divided the genus into six sections including three new sections, G. sect. Pseudodistichi, G. sect. Brachycaules and G. sect. Acinacifolii. We also reinstate G. suavis to the specific rank. Furthermore, two new species, G. armeniacus Jun Y. Zhang, B. Xu & Yue H. Cheng and G. minjiangensis Jun Y. Zhang, B. Xu & Yue H. Cheng, are described and illustrated. A key to six sections of the genus is presented.

Gastrochilus balangshanensis, a new orchid species from the Balang Mountain, Sichuan Province, Southwest China, is described and illustrated. It morphologically resembles G. affinis, but differs in having shorter stems, a reniform epichile and a sub-hemispherical hypochile (spur), obtuse-rounded at the apex. The results of molecular phylogenetic analyses based on nuclear ribosome internal transcribed spacer (nrITS) and four chloroplast DNA markers (matK, psbA–trnH, psbM–trnD and trnL–F) from 50 Gastrochilus species indicate that G. balangshanensis is closely related to G. heminii and G. bernhardtianus, also endemic to the Hengduan Mountains. The novelty is a branch and trunk epiphyte in mixed coniferous forest.

Gastrochilus jiuzhaigouensis (Orchidaceae), a new orchid species epiphytic on tree branches on the bank of an alpine lake at the famous Jiuzhaigou National Park in China, is described and illustrated. It differs from its morphologically similar species, G. bernhardtianus, by its shorter stems, obliquely linear-lanceolate leaves, reniform and revolute epichile without ornamentation, and the absence of a middle ridge at central callus of the epichile. To test its species status, sequences of the nuclear ribosomal internal transcribed spacer (nrITS) and four chloroplast DNA markers (matK, psbA-trnH, psbM-trnD, and trnL-F) were newly generated. Molecular phylogenetic analyses including 53 accessions of Gastrochilus species resolved it within the same clade as G. bernhardtianus, but with distinct boundary. Both morphological differences and phylogenetic evidence supported it a species new to science.

Campylotropis pinetorum is a widespread and morphologically varied species including three subspecies: subsp. pinetorum, subsp. velutina, and subsp. albopubescens. However, our recent extensive observations indicated that C. pinetorum subsp. albopubescens, the only taxon in the genus that can form dominant communities via rootstocks, is clearly distinguished from subsp. pinetorum and subsp. velutina due to its distinct morphological characters: ovate to ovate-triangular stipules; branches, inflorescence rachises, calyces, and both surfaces of leaflets densely white pubescent; longer and wider bracts; purplish-red flowers; standard without green spots; pods without net veins; and presence of both sexual and vegetative reproduction types. Therefore, C. pinetorum var. albopubescens, the basionym of C. pinetorum subsp. albopubescens, is elevated to the species rank as C. albopubscens (Iokawa & H.Ohashi) M.Liao & B.Xu, stat. nov.