The reproductive organs and mating biology of angiosperms exhibit greater variety than those of any other group of organisms. Flowers and inflorescences are also the most diverse structures produced by angiosperms, and floral traits provide some of the most compelling examples of evolution by natural selection. Given that flowering plants include roughly 250,000 species, their reproductive diversity will not be explained easily by continued accumulation of case studies of individual species. Instead a more strategic approach is now required, which seeks to identify general principles...