Abstract: Biomass structure and growth of reproductive ramets of Setaria viridis (L.) Beauv and S. glauca (L.) Beauv were compared in the field. Biomass of reproductive ramets had large variation between populations within each species. Coefficients of variation in biomass constituents were low, being 11.11%-22.77% in Setaria viridis and 12.41%-26.82% in Setaria glauca, respectively. Biomass of reproductive ramets increased in a power function with increasing plant height and total biomass, and they showed a similar allometric power growth pattern. The coefficients of determination R² of fitted equations were between 55% and 71% in Setaria viridis and between 62% and 81% in Setaria glauca. Plant height was the only parameter that had a significant difference between species. Reproductive allocation and sheath biomass allocation showed significant differences. The results demonstrated that, for both species under the same environment, biomass component and growth can be similar or different both within and between species, which is controlled by the interaction between environmental and genetic factors.

Key words: species diversity, Oligostachyum oedogonatum, evergreen broad-leaved forest., Phyllostachys edulis, addition effect