Repeated Evolution of Dioecy from Monoecy in Siparunaceae (Laurales)

摘要: Siparunaceae comprise Glossocalyx with one species in West Africa and Siparuna 65 the neotropics; all have unisexual flowers, 15 are monoecious, 50 dioecious. Parsimony maximum likelihood analyses of combined nuclear ribosomal ITS chloroplast trnL-trnF intergenic spacer sequences yielded almost identical topologies, which were used to trace evolution two sexual systems. The African species, is dioecious, was sister neotropical monoecious formed a grade basal large dioecious Andean clade. Dioecy evolved second time within grade. Geographical mapping 6,496 herbarium collections from sorted by system showed that monoecy confined low-lying areas (altitude < 700 m) Amazon basin southern Central America. only morphological trait strong phylogenetic signal leaf margin shape (entire or toothed), although this character also correlates altitude, probably reflecting selection on shapes temperature rainfall regimes. data do not reject molecular clock, branch lengths suggest shift dioecy lowlands occurred many million years after ancestor