Phenotypic evolution is restrained by complex developmental processes.

The paper, "Evolution and development of inflorescence architectures" by Przemyslaw Prusinkiewicz, Yvette Erasmus, Brendan Lane, Lawrence D. Harder and Enrico Coen [Science, 316, 1452-1456 (2007)], sets to accomplish a longstanding goal: to explain, for the first time, how and to what extent developmental constraints restrict phenotypic evolution. Prusinkiewicz and collaborators provide a relatively simple model that accounts for the variety of patterns of inflorescence architecture found among angiosperms, in which only a few of all possible types are observed.