INTERHABITAT VARIATION IN GROWTH-CHARACTERISTICS OF TEMPERATE HERBACEOUS PERENNIALS

Growth characteristics were investigated in 40 temperate herbaceous pe rennial species in relation to habitat. Some forest plants completed l eaf development and shoot elongation before and during canopy closure. This rapid foliation involved expansion of only a small number of fol iage leaves, disappearance of scale leaves, and a reduced shoot height . These species showed a determinate growth habit and early initiation of flowering. These are characteristics considered to have evolved in association with shade stress. In contrast, plants mainly found in ex posed sites with a tall-herb vegetation continued leaf development and shoot elongation even in mid-August. These species possessed a determ inate growth habit, not investing photosynthates into sexual organs at least during early vegetative growth, and showed late initiation of f lowering. These characteristics appear to be related to competition fo r light. Plants in exposed sites without tall herbs also continued lea f development in mid-August, but they had rosette forms coupled with i ndeterminate growth habit and varying time of flowering initiation. Th ese traits allow the plants to make maximum use of the growing season and are advantageous to vegetative regeneration after disturbance. On the basis of the leaf-development duration in this study and dormant s tates obtained in a previous study, three growth-rhythm categories can be recognized in relation to habitat.