Arundinella stenostachya, a new species, is described and illustrated. It is morphologically similar to A. decempedalis and A. bengalensis, but differs from the former species by the length of panicle branches, type of trichome on nodes and pedicels length, and from the latter in height and diameter of culms, the length and width of leaf blades, pedicels length, and the length of panicles and branches. The new species has been mistakenly identified as A. decempedalis and A. bengalensis. Molecular analyses based on ITS sequences also support A. stenostachya as a distinct species. [ABSTRACT FROM AUTHOR]