The flora of the Hengduan mountains of China includes the lady's slipper orchids, Cypripedium spp., many of which are endemic to China. Over-collected by plant enthusiasts, used medically by local people and disturbed by natural disasters, many Cypripedium species are threatened. Cypripedium forrestii was first collected on Yulong Snow Mountain near Lijiang in north-west Yunnan. This sacred mountain for the Naxi people has long been a famous scenic spot and the only know habitat of C. forrestii. Later, another habitat was found in Haba Mountain of Diqing, c. 20 km away. Cypripedium forrestii has a narrow distribution and extremely small population, and is categorized as Critically Endangered on the IUCN Red List and on the threatened species list of China's higher plants. The absence of systematic field surveys and the small number of herbarium records of C. forrestii have hampered conservation of this species.
In July 2022, as a part of the conservation project Plant Species with Extremely Small Populations supported by Yunnan Forestry and Grassland Bureau (2021SJ14X-09), we surveyed the potential habitat of C. forrestii in north-west Yunnan to update knowledge of this threatened species. We found the species in four locations. The population on Yulong Snow Mountain comprises c. 60 individuals and is threatened by potential landslides and tourism. On Haba Snow Mountain of Diqing Tibetan Autonomous Prefecture, we found several populations, with a total of > 1,000 individuals. We also found the species in two locations, with c. 100 individuals in each, near Bita Lake and beside a country road near Shangri-la city.
Anthropogenic disturbance and habitat degradation are the main threats to C. forrestii. Most of the populations on Haba Mountain are large in size, little disturbed, healthy and self-sustainable. These populations will be valuable for artificial propagation and reintroduction projects. Preliminary conservation work for the species, both in situ and ex situ (artificial pollination and tissue culture), is being carried out by Kunming Institute of Botany and Lijiang Alpine Botanic Garden. We plan to carry out further research on C. forrestii, especially on population dynamics, genetic structure and pollination ecology, to guide future conservation of the species.