This collection of reviews by leading investigators examines plant reproduction and sexuality within a framework of evolutionary ecology, providing an up-to-date account of the field. The contributors discuss conceptual issues, showing the importance of sex allocation, sexual selection and inclusive fitness, and the dimensions of paternity and maternity in plants. The evolution, maintenance, and loss of self-incompatibility in plants, the nature of 'sex choice' in plants, and sex dimorphism are all explored in detail. Specific forms of biotic interactions shaping the evolution of plant reproductive strategy are discussed, and a taxonomically based review of the reproductive ecology of non-angiosperm plant groups, such as bryophytes, ferns, and algae, is presented. Together these studies focus on the complexities of plant life cycles and the distinctive reproductive biologies of these organisms, while showing the similarities between nonflowering plants and the more thoroughly documented flowering species.