Gelidocalamus zixingensis (Poaceae, Bambusoideae, Arundinarieae), a new species from southern China revealed by morphological and molecular evidence

The genus Gelidocalamus T. H. Wen, endemic to southern China, is a small but taxonomically problem-atic genus of Arundinarieae (Poaceae, Bambusoideae). During field work, a population of Gelidocalamus from Zixing, Hunan, was discovered, appearing to be distinct from our previously identified collection. Comparisons of the population of Zixing were performed by using scanning electron microscopy (SEM) and a plastid genome-based phylogeny. Morphologically, it was mostly similar to G. multifolius, but dif-fered by culm leaf erect with densely white pubescence, apical branch sheath much longer than the inter -nodes and foliage leaf larger. Phylogenetically, the new species was well-supported as a sister to the clade of G. multifolius + G. tessellatus, and the above three taxa were clustered in the Shibataea clade (IV) of Arundinarieae. Thus, the new species, formally named as Gelidocalamus zixingensis W.G.Zhang, G.Y.Yang & C.K.Wang, was described and illustrated herein.