Description: This rare fern is a small plant, similar to its commoner relative, Wilson's Filmy-fern. Both superficially resemble tufts of moss, and grow in deep shade in humid conditions. It can be separated from Wilson's Filmy-fern by several features, of which the easiest to see is the fact that the indusium is toothed (untoothed in Wilson's Filmy-fern). The indusium is the two-lipped structure covering the sporangium which are produced at the ends of the lobes of the leaves. Most Northern Ireland sites for this fern are in Co. Fermanagh.

All names: Hymenophyllum tunbrigense (L.) Smith

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

iNaturalist: Hymenophyllum tunbrigense at iNaturalist World Species Observations database.