A century of research on heterostylous plants has passedsince the publication of Charles Darwin's book "TheDifferent Forms of Flowers on Plants of the Same Species" in1877 summarizing his extensive observations and experimentson these complex breeding systems involving geneticpolymorphisms of floral sex organs. Since then heterostylousplants have provided a rich source of material forevolutionary biologists and today they represent one of theclassic research paradigms for approaches to the study ofevolution and adaptation. The present book is the firstmodern and comprehensive accont of the subject. In 10chapters it is concerned with the evolution, genetics,development, morphology, and adaptive significance ofheterostyly. Broad syntheses of research on heterostyly aswell as new theoretical ideas and experimental data areincluded.