This paper describes Microstegium japonicum (Miq.) Koidz. as a newly recorded species of grass to Taiwan. It was collected first by M. T. Kao in 1954, but misidentified as M. somae. M. japonicum is easily distinguishable from M. somae: the former has 1-awned spikelets and awn borne only on the fertile lemma, whereas the latter has 3-awned spikelets and awns borne on upper glume and both lemmas.