Hemiboea pterocaulis comb. et stat. nov. (Gesneriaceae), a new critically endangered species segregated from H. subcapitata

Hemiboea subcapitata C. B. Clarke is a widespread and morphologically variable species in the family Gesneriaceae. Hemiboea subcapitata C. B. Clarke var. pterocaulis Z. Y. Li was first published from Guangxi, China. Extensive observations of morphology and phenology, as well as reconsideration of the original description, have, however, revealed that H. subcapitata var. pterocaulis and H. subcapitata var. subcapitata are consistently differentiated. Furthermore, the present phylogenetic analyses using the nuclear ITS and plastid trnL-F DNA sequences also revealed that the sampled individuals identified as H. subcapitata var. pterocaulis grouped together and were clearly separated from typical H. subcapitata. Based on these analyses, we elevate the variety to the status of species, as Hemiboea pterocaulis (Z. Y. Li) J. Huang, X. G. Xiang & Q. Zhang.