Arundinellamainlingensis (Poaceae), a new species from Xizang, China.

Arundinellamainlingensis (Poaceae), a new species from Xizang, China is described and illustrated. This new species forms a sister group relationship with A.yunnanensis on the molecular phylogenetic tree, sharing common morphological characteristics such as ligule extremely short, glumes glabrous and 4-5 mm long and lemma with an apical awn. Arundinellamainlingensis differs from A.yunnanensis in having stems with 3 or 4 nodes, clustered basal leaves, densely covered with tubercle-based hairs on the margins and the adaxial surface, less cauline leaves and lower florets that are male or neuter with short anthers about 1.2 mm long. Arundinellamainlingensis is primarily found in south-eastern Xizang, including Nyingchi, Mainling and Bomê, whereas A.yunnanensis is only observed in Gongshan, Yunnan. These differences further reinforce the classification of the two as distinct species.