In plants that produce both closed, obligatory self-pollinated (cleistogamous) and open, potentially out-crossed (chasmogamous) flowers, suboptimal conditions typically favour production of cleistogamous flowers. Munguía-Rosas et al. study the effects of shade and drought on Ruellia nudiflora and find that cleistogamous flowers are produced earlier under shaded conditions whilst chasmogamous flowers are produced for shorter periods; however, resources are preferentially allocated to those chasmogamous flowers receiving larger pollen loads. The results demonstrate complex interactions between environment and reproduction in cleistogamous plants.
