The plant Orchidantha yunnanensis P. Zou, C.F. Xiao & Škorničk of the family Lowiaceae was described based on living plants in Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, in 2017. The living plants were originally identified as Orchidantha chinensis T.L. Wu, collected from Malipo county in south-east Yunnan province in 2001. However, the authors recognized that the cultivated plants were not O. chinensis and they were therefore described as O. yunnanensis (P. Zou et al., 2017, Phytotaxa, 302, 181–187). Orchidantha yunnanensis was thought to be extinct in the wild because no living plants were discovered during resurveys in the location of the original collection. The species may have been overcollected for medicinal uses.
During April 2018–March 2019 surveys were carried out in south-east Yunnan with the joint support of China's National Science and Technology Basic Resources Investigation Programme for Surveys and Germplasm Conservation of Plant Species with Extremely Small Populations in South-west China (grant no. 2017FY100100). Fifteen clumps of O. yunnanensis were discovered in one locality in Hekou Yao Autonomous County, c. 200 km from the original collection site. With such a small population size and with poor natural regeneration, O. yunnanensis needs to be categorized as a Plant Species with an Extremely Small Population (W. Sun et al., 2019, Trends in Plant Science, 24, 4–6). In April 2018 we collected vegetative material for propagation and ex situ cultivation in Kunming Botanical Garden; several plants have been successfully propagated and are growing well in a greenhouse.
Our survey, and information obtained from local people, indicated that the main threats to this species are habitat degradation and poor fruiting. The single known location of O. yunnanensis is not within a protected area. As the population is facing a high risk of extinction, protection of the known individuals and their habitat is critical, and research is also required on the reproductive biology and poor fruiting of the species. Yunnan Key Laboratory for Integrative Conservation of Plant Species with Extremely Small Populations and South China Botanical Garden, Chinese Academy of Sciences, are now cooperating to study these matters. Further surveys for the species are also required in the karst region of south-east Yunnan and the adjacent area of northern Viet Nam.
