cleistogamy

300px|thumb|Chasmogamous (a) and cleistogamous (b) flowers of Viola pubescens. Arrows point to structure.

Cleistogamy is a type of automatic self-pollination of certain plants that can propagate by using non-opening, self-pollinating flowers. Especially well known in peanuts, peas, and pansies, this behavior is most widespread in the grass family. However, the largest genus of cleistogamous plants is Viola. Cleistogamy is promoted in the tomato plant by a modification of floral structures. This modification includes formation of a stigma enclosing floral structure.