Environmental control of cleistogamy in prairie grass (Bromus unioloides H.B.K.)

Abstract

In long days (16 hours) flowers of prairie grass (Bromus unioloides H.B.K.) were almost invariably cleistogamous. In shorter photoperiods chasmogamous flowers were the rule provided soil moisture was high. Chasmogamy was attended by greater anther length but later anthesis than occurred in the cleistogamic condition. Filaments and lodicules were small in cleistogamous flowers and autogamous pollination occurred soon after emergence from the leaf sheath.