Thyrsopteris is a genus of
tree fern. It contains a single living species, Thyrsopteris elegans, endemic to the
Juan Fernandez Archipelago off the coast of Chile. Thyrsopteris is the only genus in the family Thyrsopteridaceae in the
Pteridophyte Phylogeny Group classification of 2016 (PPG I).[1] Alternatively, the genus may be placed in the subfamily Thyrsopteridoideae of a more broadly defined family
Cyatheaceae,[2] the family placement used in Plants of the World Online as of November 2019[update].[3] The oldest records of the genus are the species Thyrsopteris cretacea and Thyrsopteris cyathindusia which were described from the
Burmese amber of Myanmar, dating to the
Cenomanian of the
Cretaceous period, around 99 million years ago.[4][5] Other fossil species include Thyrsopteris antiqua from the Upper Cretaceous of Chile and Thyrsopteris shenii from the
Paleogene of
King George Island, Antarctica[6][5] A thyrsopterid
rachis is also known from the Upper Cretaceous of Japan.[7]