Molecular phylogeny of the genus Arum (Araceae) inferred from multi-locus sequence data and AFLPs

For centuries the wonderful looking, but foul smelling, Arum lilies have fascinated botanists. The floral odour of many species is believed to mimic faeces—the oviposition substrate of their pollinators, mainly coprophilous flies and beetles. But not all of the 29 Arum species produce a bad floral smell. The genus has evolved a variety of pollination mechanisms, including sweet and wine-like odours, and maybe even pheromone mimicry. In order to study the evolution of the pollination syndromes in Arum, a detailed and reliable phylogeny is a crucial basis. Here we present the first detailed molecular phylogeny of the genus Arum. By combining three chloroplast and one nuclear loci, as well as AFLPs, a highly resolved tree with good statistical support was obtained. The phylogeny is in most parts in congruence with the traditional classification of the genus. By comparing the phylogeny with the data on the pollination biology of the genus we could show that the mimicry of faeces is the oldest and most basal pollination mechanism, but is also present in the youngest and most derived species. The phylogeny presented here will help to study the evolution of deceptive pollination mechanisms in Arum.