Summary

Abstract: Orchidaceae is a diverse, globally important plant family with high conservation assessment and prioritization requirements. The checklist of Orchidaceae in Mongolia was updated based on herbarium materials, literature, and field observations. Mongolian orchids were revised as comprising 26 taxa belonging to 14 genera with major updates were conducted on Herminium and Epipactis. In particular, H. alaschanicum, previously noted in the Alashan Gobi region, was added to the flora of Mongolia based on literature and type specimens. Epipactis helleborine and E. palustris were excluded from the Mongolian flora owing to the absence of herbarium specimens and wild collection from Mongolia. Assessment of all orchid species at the national level resulted in 1, 4, 7, 11, and 2 species as critically endangered (CR), endangered (EN), vulnerable (VU), near threatened (NT), and data deficient (DD), respectively, according to IUCN criteria. Species richness and conservation gap analyses of 970 georeferenced orchid records based on 0.5  0.5 grid cells across 16 phytogeographical regions of Mongolia, showed that four phytogeographical regions, Khangai, Khuvgul, Khentii and Mongolian Dauria, have a high number of orchids. Regrettably, most orchid-rich locations in Mongolia are not fully within protected areas, highlighting the need for protection management updates. Based on herbarium collections, we prepared grid distribution maps of the 26 taxa using 40 x 40 km2 grids. Photographs of 18 taxa taken during fieldwork were included, providing valuable information on species morphology and typical habitat.