Flowers that self-shade reduce heat stress and pollen limitation.

C lower than those that remained open and unshaded. In our wiring experiment, unencumbered R. coulteri controls were 40% more likely to produce seeds than flowers that were either permanently open or closed. Without added pollen, control flowers produced 2x more seeds than flowers wired open and 8x more than those wired closed. However, pollen addition eliminated the effects of wiring and increased capsule weight and seed production. This suggests that pollen limitation was responsible for observed differences in the wiring treatments. Pollinators may prefer control flowers over those that were wired open or closed; petal shading may make flowers cooler and more attractive to pollinators. Conclusions Petal shading may be a behavior that allows flowers to reduce heat stress and increases their chances of pollination and seed set. This article is protected by copyright. All rights reserved.