Temperature relations of seed germination in Ruellia humilis, and ecological implications ( Acanthaceae).

Freshly-matured seeds of Ruellia humilis (Acanthaceae) germinate after prolonged incubation at temperatures exceeding those in the habitat at the time of seed dispersal in autumn. However, in the field, seeds are exposed to effective stratification temperatures during winter, and germination occurs in spring. The number of days with stratifying temperatures (0.5-10oC) in all parts of the range is sufficient to satisfy the chilling requirement. Thus, germination need not be dependent on ecotypes or races with dormancy and germination characteristics that are closely adapted to local environmental conditions. -from Authors