Adiantum: A plant genus of the family Pteridaceae. Members contain TRITERPENES. Some species in this genus are called maidenhair fern which is also a common name occasionally used for Lygodium (FERNS) and POLYPODIUM.Ferns: Seedless nonflowering plants of the class Filicinae. They reproduce by spores that appear as dots on the underside of feathery fronds. In earlier classifications the Pteridophyta included the club mosses, horsetails, ferns, and various fossil groups. In more recent classifications, pteridophytes and spermatophytes (seed-bearing plants) are classified in the Subkingdom Tracheobionta (also known as Tracheophyta).Diuron: A pre-emergent herbicide.