Seedling survival and flowering of Rumex obtusifolius L. in various habitats.

Abstract

The seedling survival and flowering of R. obtusifolius in pasture, meadow, forest edge and bare ground sites were surveyed and discussed in relation to the environments of the surveyed sites.The results are as follows:1. The number of plants surviving in the forest edge site decreased most slowly. The number in the bare ground site declined drastically in winter and gradually from spring to autumn, while the number in the pasture and meadow sites declined at a relatively constant rate (Fig. 3).2. The higher the rate of bare ground area, the higher was the mortality in winter. Death in winter was due to the dessication of roots by frost heaving (Table 3, Fig. 4).3. The flowering rate was highest in the bare ground site and lowest in the forest edge site. Relative light intensity seemed to have a positive effect on the rate (Tables 2 and 5).4. The habitats suitable for individual survival were not always favourable to reproduction, and it was suggested that the population size of this weed might be regulated by this balance (Table 5, Fig. 3).