A new species, Gymnostachyum morsei Y.F.Deng, is described from Guangxi, China. A morphological description, taxonomic comments, distribution and habitat data, preliminary conservation status, illustration, and key to Chinese species in the genus are provided. The new species grows on rocks in limestone hill forest. It is similar to G. subrosulatum H.S.Lo, but differs in having lanceolate leaves with a narrowly cuneate base decurrent onto the petiole, and a trifurcating racemose inflorescence (vs suborbicular to broadly cordate leaves with a slightly cordate to rounded base, and a thyrse inflorescence in G. subrosulatum).