Strange rocks, forgotten ferns and rare sedges; rediscovering Filmy Ferns and overlooked habitats in the Slieve Aughty Mountains (H9 and H15)

The geologist and botanist G.H. Kinahan noted the occasional presence of Hymenophyllum wilsonii and H. tunbridgense on cliffs in the Slieve Aughty Hills of Clare and southeast Galway in the 1860’s. There are no subsequent records of the ferns in the hills until H. wilsonii was seen in 2006, but in a different habitat to the escarpments of Kinahan. Here we report 10 new records of the 2 species in Slieve Aughty. All records were close to the boundary between Silurian slate and Devonian sandstone or conglomerate. This boundary is frequently marked by an escarpment and the occurrence of ‘cornstone’ or impure limestone between the slate and conglomerate, as first reported by Kinahan. This more basic rock provides a habitat for some lime requiring species. At one site a fen occurs between two such escarpments and is the location of the rare Eriophorum gracile, a new vice-county record for Clare (H9).