title: Floral gigantism in Rafflesiaceae.
abstract: Species of Rafflesiaceae possess the world's largest flowers (up to 1 meter in diameter), yet their precise evolutionary relationships have been elusive, hindering our understanding of the evolution of their extraordinary reproductive morphology. We present results of phylogenetic analyses of mitochondrial, nuclear, and plastid data showing that Rafflesiaceae are derived from within Euphorbiaceae, the spurge family. Most euphorbs produce minute flowers, suggesting that the enormous flowers of Rafflesiaceae evolved from ancestors with tiny flowers. Given the inferred phylogeny, we estimate that there was a circa 79-fold increase in flower diameter on the stem lineage of Rafflesiaceae, making this one of the most dramatic cases of size evolution reported for eukaryotes.
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA 02138, USA. cdavis@oeb.harvard.edu
authors.forename: Charles C
authors.initials: CC
authors.lastname: Davis
authors.forename: Maribeth
authors.initials: M
authors.lastname: Latvis
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Nickrent
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Wurdack
authors.forename: David A
authors.initials: DA
authors.lastname: Baum
mesh_terms: D001499:Bayes Theorem; D005075:Biological Evolution; D019665:Euphorbiaceae / Q000033:anatomy & histology / Q000145:classification*; D035264:Flowers / Q000033:anatomy & histology*; D017343:Genes, Plant; D016013:Likelihood Functions; D019684:Magnoliopsida / Q000033:anatomy & histology* / Q000145:classification* / Q000235:genetics; D010802:Phylogeny