Gastrodia umbrosa B.Gray (Orchidaceae, Gastrodieae): a new mycoheterotrophic orchid endemic to the Atherton Tableland, Queensland, Australia

Gastrodia umbrosa B.Gray, a new mycoheterotrophic orchid is described and illustrated. It was recently discovered from the submontane rainforest of the Atherton Tableland in north Queensland. Gastrodia umbrosa is morphologically similar to G. queenslandica Dockrill but differs in having dark purplish brown flowers with tepals fused for almost the entire length as opposed to brownish orange flowers and tepals fused for two-thirds the length. A taxonomic key to tropical Queensland Gastrodia species is provided.