In this supplement to his celebrated series of books on the Cattleya alliance of orchids, Carl Withner joins with Patricia Harding to explore "the debatable epidendrums." Carl Linnaeus established the genus "Epidendrum" in 1753 to include the mostly epiphytic orchid plants being sent to him from tropical America. Over time the genus grew to include more than 1000 species of evergreen epiphytic, lithophytic, or terrestrial orchids. Some of these epidendrums...