In 1830, John Henslow introduced his pupil Charles Darwin in the fascinating world of floral polymorphisms. Specifically he presented him the case of some plant species hermaphrodites having two floral forms that differ in height and arrangement of female sexual structures: the pistils. In a floral morph, stigmas are located above the male structures (stamens), while in the opposite morph, the stigmas are located below the stamens. Trying to unravel the origin and consequences of this fascinating reproductive mechanism that some plant species have, undoubtedly contributed to shaping the curious and critical character that led the young Darwin to formulate years later his hypothesis of Natural Selection. Since then, a myriad of researchers are still trying to decipher the mysteries surrounding this refined reproductive mechanism in some plants. This video explains what is heterostyly: a floral polymorphism that attracted Darwin´s attention to the point that he devoted a book to its study. The video gives an overview answering questions as: What is heterostyly?, What good is this sexual system? How did it originate? or How can we study it? Heterostyly consisting polymorphism is the presence of two or three floral shapes within the same plant species. The advantages of this system of reproduction, and its origin are matters of scientific controversy. The video explains the contributions has made in this topic the Group of Ecology and Evolution at the University of Vigo