Chasmogamous Flowering in Viola palustris L.

Abstract

AFTER a short burst of chasmogamous flowering in early spring, plants of V. palustris, like those of many other violet species, produce a succession of cleistogamous flowers throughout the summer. Such a change in flowering habit could be associated with changes in day-length, as in V. fimbriatula and V. papilionacea with which Allard and Garner¹ obtained chasmogamous flowers only in short days and cleistogamous flowers in long days. With several other violet species Chouard² has obtained chasmogamous flowering only in short day-lengths (for example, V. odorata), or after exposure to winter temperatures (for example, V. silvestris), or after both winter temperatures and subsequent short-day treatment (for example, V. hirta).