Since 1953, we have conduced continuous field studies on the bamboo (Phyllostachys bambusoides) stands of Chiba. A part of these stands began flowering in 1960. The emergence of season-insensitive, short slender bamboo (similar to dwarf bamboo) precedes the bamboo flowering. The regenerative process is short slender bamboo with small leaves as undergrowth foretelling flowering (R's)→ regenerated, short slender bamboo with small leaves (Rs)→a new-generation of short, slender bamboo with large leaves (Rl)→a new generation of short, slender bamboo with medium-sized leaves (Rm)→a tall, regular growth of bamboo (T). Some of the short slender bamboo flower (Rf), but some of them do not flower (Rnf). The productive structure develops from the grassy type to the herbacious type after flowering (Rs→T). Leaf characteristics and dry matter distribution are measured according to the regenerating stages. The most characteristic stage, Rl, appears to play an important role in bamboo regeneration because of its large amount of photosynthetic biomass and the high photosynthetic rates. Rm is a miniature version of normal tall bamboo.