Interhabitat variation in growth characteristics of temperate herbaceous perennials

Abstract

Growth characteristics were investigated in 40 temperate herbaceous perennial species in relation to habitat. Some forest plants completed leaf development and shoot elongation before and during canopy closure. This rapid foliation involved expansion of only a small number of foliage 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 exposed sites with a tall-herb vegetation continued leaf development and shoot elongation even in mid-August. These species possessed a determinate growth habit, not investing photosynthates into sexual organs at least during early vegetative growth, and showed late initiation of flowering. These characteristics appear to be related to competition for light. Plants in exposed sites without tall herbs also continued leaf development in mid-August, but they had rosette forms coupled with indeterminate growth habit and varying time of flowering initiation. These 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 states obtained in a previous study, three growth-rhythm categories can be recognized in relation to habitat. Key words: growth form, growth habit, growth rhythm, leaf-development duration, flowering initiation, shade stress, disturbance, competition.