The evolution of flower morphology is beginning to be understood through research on the genetic mechanisms of reproductive development in angiosperms (flowering plants). The model organism Arabidopsis thaliana (thale cress) has figured prominently in these studies. Although Arabidopsis was the first plant completely sequenced (in 2000), earlier genetic studies of Arabidopsis (beginning in the late 1980s) paved the way for evolutionary interpretations of the molecular processes underlying floral diversity.