This is the cross between Scaly Male-fern and Male fern (Dryopteris affinis x D. filix-mas). It has been rarely recorded in Northern Ireland, but we do not know if this is because it is really rare, or because botanists fail to spot it in the field as it is so like its parent species.
All names: Dryopteris affinis x filix-mas (D. x complexa) Fraser-Jenkins; Dryopteris x complexa Fraser-Jenkins; Dryopteris affinis x filix-mas; Dryopteris x tavelii Rothm.; Dryopteris borreri x felix-mas