This paper deals with the taxa of tribe Arundinarieae Steud. subtribe Pleiobalastinae Keng and Keng f. which comprised three genera (Pseudosasa Makino, Pleioblastus Nakai and Brachystachyum Keng) when it was established in 1957. With the analysis of morphological characters and geographical distribution, a number of revisions connected with the taxon are made as follows:

     (1)  Genus Brachystachyum Keng is transferred to the tribe Shibataeeae Nakai ac-

cording to its false inflorescence.

     (2)  Genus Pseudosasa Makino is transferred to subtribe Sasinae Keng f. according to our study on the numerical taxonomic method.

     (3)  Some species of Pleioblastus Nakai established by Keng and Keng f. should be

revised. Pleioblastus actinotrichus (Merr. and Chun) Keng f. should be Ampelocalamus actinotrichus (Merr. and Chun) S. L. Chen, T. H. Wen and G. Y. Sheng in subtribe Tham-

nocalaminae Keng f.; Pleioblastus dolichanthus (Keng) Keng f. is the synonym of Sinobam-

busa tootsik (Sieb.) Makino, belonging to tribe Shibataeeae Nakai. The rest species remain in this genus. Since the genus Pleioblastus is related to genus Arundinaria Michaux., subtribe Pleioblastus Keng and Keng f. does not seem to have a reason to be retained as a subtribe in tribe Arundinarieae Steud., according to the newest Code (1978). A part of it should be a synonym of subtribe Arundinariinae and we may cite it as follows: Subtribe Arundinariinae——Subtribe Pleioblastinae Keng and Keng f. pro parte, syn. nov. The other parts of it should be transferred to other subtribes or tribes.

      In addition, one new variety in Branchystachyum, two new species, one new variety in Pseudosasa and six new species, three new varieties in Pleioblastus, are described in this paper.