silver standard: a monetary standard under which the basic unit of currency is defined by a stated quantity of silver
standard: the value behind the money in a monetary system
polypodiaceae: ferns: a large family that in some classification systems has been subdivided into several families (including Aspleniaceae and Blechnaceae and Davalliaceae and Dennstaedtiaceae and Dryopteridaceae and Oleandraceae and Pteridaceae)