The natural history of the genus Cypripedium (Orchidaceae)

The genus Cypripedium is one of five monophyletic genera within slipper orchids. Nuclear ribosomal ITS, nuclear low copy gene (ACO) and plastid data were used for molecular clock analyses. According to these analyses, the most recent common ancestor of Cypripedium appeared in the early Eocene. The Irapeana section is the oldest phylogenetic line within Cypripedium. The analyses indicate that after the Middle Eocene Climatic Optimum (c. 41 Ma) three main evolutionary lineages were split. Other important evolutionary processes took place in the late Oligocene-early Miocene. In this period, there were numerous divergence events within species groups characterized by transcontinental disjunction.