The rediscovery of the rare Vietnamese endemic redefines generic limits in the Scirpo-Caricoid Clade (Cyperaceae).

For those familiar with boreal bogs and wet tundra, species of ("the cotton grasses") will undoubtedly represent some of the most striking and memorable taxa they have encountered. This small genus of 20 Holarctic sedge species (Cyperaceae) is remarkable because its inflorescences produce large, brilliantly white to rusty-red cottony masses when its flowers develop a perianth of highly elongated bristles after anthesis. In this study, we document the rediscovery of , a narrow Vietnamese endemic known from only two collections made approximately 7 km apart near Sa Pa in Lào Cai Province over 75 years ago.