scented fern n fern of eastern North America with pale green fronds and an aroma like hay n sweetly scented African fern with narrow bipinnate fronds n common perennial aromatic herb native to Eurasia having buttonlike yellow flower heads and bitter-tasting pinnate leaves sometimes used medicinally Synonym(s) hay-scented hay-scented fern boulder fern Dennstaedtia punctilobula Mohria caffrorum tansy golden buttons Tanacetum vulgare