The Genus Lyginopteris is a group of fern-like plants that thrived during the Carboniferous and Permian periods. Some synonyms for this unusual plant group include Lyginopteridales and Lyginopteridaceae. Lyginopteridales refer to the order of the plant, which includes all species in the Lyginopteris genus. Lyginopteridaceae, on the other hand, refers to the family of the plant, which shares characteristics with other fern species like tree ferns and bracken ferns. Other synonyms include Lyginopteris sigillarioides, which is a specific species that was commonly found in ancient coal swamps. The Genus Lyginopteris is an important fossil group that provides important insights into the evolution of ferns and other plants in prehistoric times.