Rediscovery of Riella alatospora (Riellaceae, Sphaerocarpales), an aquatic, South African endemic liverwort previously known from a now largely transformed type locality

► Riella alatospora is an endemic South African liverwort thought to be extinct. ► This species was known from a single locality and has not been collected since 1932. ► We report a new locality representing the rediscovery of the species. ► The species was grown in the laboratory from sediments of a salt pan. ► We provide a detailed description, spore images and illustrations.