A Reanalysis of Relationships among Calypsoinae (Orchidaceae: Epidendroideae): Floral and Vegetative Evolution and the Placement of Yoania

Calypsoinae are a small, largely temperate subtribe that are diverse with respect to trophic strategy (many species have an unusual winter leaf and several are leafless) and pollinium stalk morphology. Here we sought to re-evaluate the placement of Yoania and recently proposed genera and to examine trophic strategy, pollinium stalk type, and geographic distribution in a phylogenetic context. We analyzed ITS and matK sequences from all accepted genera using maximum likelihood and parsimony on individual and combined data sets. The only supported disagreement among trees was between the combined ML and parsimony analyses for the placement of Dactylostalix and Ephippianthus; the trees from one analysis reflected the nuclear pattern, while the other resembled the plastid pattern. A group of genera related to Calypso and a group related to Corallorhiza were resolved. Yoania is closely related to Calypso; the recently proposed Yunorchis is a species of Yoania, while Didiciea is part of Tipularia. Examining leaf morphology on the tree revealed two originations of the winter leaf morphology and four losses of leaves (and shifts to mycoheterotrophy). Pollinium stalks evolved in three directions, two of which resulted in epidermally-derived stalks (tegulae) and one that comprises the entire rostellum (a hamulus). Biogeographic analysis suggests a NewWorld origin for the subtribe, with two major shifts to the Old World and one shift back to the New World.