Growth rules based on the modularity of the Canarian Aeonium (Crassulaceae) and their phylogenetic value

Growth forms of 22 species of Aeonium (Crassulaceae) were quantified. Since all species are simple in their modular construction, models were developed to predict module length, branching mode and flowering probability using linear and logistic regression. When combined, the parameters of these models are species specific. A discriminant analysis generates a statistically significant separation of species at the level of phylogenetic sections. The results therefore demonstrate the phylogenetic value of growth rules in plants. This dynamic approach strongly contrasts with the traditional static view on forms in systematics and morphology. It also leaves scope for predicting the evolutionary pathways of morphological change which have caused the great diversity of growth forms in the genus Aeonium.