How (much) do flowers vary? Unbalanced disparity among flower functional modules and a mosaic pattern of morphospace occupation in the order Ericales

Marion Chartier, Stefan Loefstrand, Anna Maria Louise von Balthazar-Schönenberger, Sylvain Gerber, Florian Jabbour, Herve Sauquet, Jürg Schönenberger

The staggering diversity of angiosperms and their flowers has fascinated scientists for centuries. However, the quantitative distribution of floral morphological diversity (disparity) among lineages and the relative contribution of functional modules (perianth, androecium and gynoecium) to total floral disparity have rarely been addressed. Focusing on a major angiosperm order (Ericales), we compiled a dataset of 37 floral traits scored for 381 extant species and nine fossils. We conducted morphospace analyses to explore phylogenetic, temporal and functional patterns of disparity. We found that the floral morphospace is organized as a continuous cloud in which most clades occupy distinct regions in a mosaic pattern, that disparity increases with clade size rather than age, and that fossils fall in a narrow portion of the space. Surprisingly, our study also revealed that among functional modules, it is the androecium that contributes most to total floral disparity in Ericales. We discuss our findings in the light of clade history, selective regimes as well as developmental and functional constraints acting on the evolution of the flower and thereby demonstrate that quantitative analyses such as the ones used here are a powerful tool to gain novel insights into the evolution and diversity of flowers.

Department of Botany and Biodiversity Research
External organisation(s)
Stockholm University, Museum national d'Histoire Naturelle, Université Paris XI - Paris-Sud
Proceedings of the Royal Society of London B: Biological Sciences
No. of pages
Publication date
Peer reviewed
Austrian Fields of Science 2012
106042 Systematic botany, 106008 Botany, 106012 Evolutionary research
Portal url