The impact of individual inaccuracy of reciprocal herkogamy on legitimate pollen deposition and seed set in a distylous self-incompatible herb

1. Heterostyly is a floral polymorphism that has evolved independently in about 28 plant families across the globe. Heterostyly is characterized by reciprocal arrangement of the anthers and stigmas and the presence of a heteromorphic self-incompatibility system, which together have been hypothesized to promote cross-pollination and to avoid interference of self-pollen and the deleterious effects of inbreeding. 2. Recent analyses have shown that the reciprocal positioning of the sexual organs in heterostylous plant species is not always perfect. Inaccuracies in the positioning of styles and anthers within populations are expected to affect both male and female fitness of plants by disturbing pollen uptake and stigmatic deposition by insects. However, at present little is known about how inaccuracies in the reciprocal positioning of the sexual organs affect stigmatic pollen deposition and subsequent seed set in heterostylous plant species. 3. In this paper, we quantified the level of reci...