hay-scented fern noun3 •Any fern of genus Dennstaetia, of many warm temperate to tropical regions. •any fern of species Dennstaedtia punctilobula, native to cool-temperate eastern North America. •A hay-scented buckler-fern, of species Dryopteris aemula, native to western Europe and Macaronesia. formshay-scented ferns