Description: This unusual plant is a fern of wet lake margins. It once grew around Lough Neagh, but successive lowerings of the lake water level rendered it extinct, and it has not been seen since 1950.

All names: Pilularia globulifera L.

Distribution Map from NBN: Pilularia globulifera at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pilularia globulifera at iNaturalist World Species Observations database.