New taxa of tribe Gastrodieae (Epidendroideae, Orchidaceae) from Yunnan, China and its conservation implication

Gastrodia longistyla, a new species of Orchidaceae from Yunnan Province, China, is described and illustrated. It is morphologically similar to Gastrodia peichatieniana, but can be easily distinguished from the latter by having a rhombic epichile, long column (6.0–7.5 mm long), and a needle-shaped appendage (1.8–3.2 mm in length) at the base of the stigma. Identification key and colour photographs are provided. A preliminary risk-of-extinction assessment, according to the IUCN Red List Categories and Criteria, is given for the new species. The plastome of G. longistyla is 30464 bp in length with GC content approximately 24.8%, and the plastome does not contain some housekeeping genes, such as matK, rpl16, or all photosynthesis genes. In addition, the G. longistyla plastome lacks an IR region. This indicates that the plastome is in the last stage of degradation.