Abstract: A comparative study of twelve species of bamboos belonging to 9 genera (12 species): Phyllostachys pubescens Mazel, Ph. bambusoides Sieb. & Zucc., Ph. nigra var. Henonis (Mitf.) Stapf., Brachystachyum densiflorum (Rendle) Keng, Chimonobambusa quadrangularis (Fenzi) Makino, Pseudosasa japonica (Sieb. & Zucc.) Makino, Shibataea chinensis Nakai, lndocalamus Migoi (Na- kai) Keng f., Pleioblastus amarus (Keng) Keng f., Sinocalamus Oldhami (Munro) McClure, Bambusa multiplex (Lour.) Raeuschel, and B. multiplex var. nana (Roxb.) Keng f., has been under-taken. In view of the middle portion of the bamboo culm which is structurally quite different from the basal portion, and more or less similar to the terminal part, it has been selected for study. Their external morphology and internal structures are briefly described. The 12 species are grouped under 9 types in accord with their configurations and structures of the vascular bundles. Subsequently, an anatomical classification of the 12 species and a key to such are proposed. A conspicuous correlation of the difference in internal structures with the growth habits of the tufted and scattered types is also discussed.