The species was first described in 1874 by
Ferdinand von Mueller in the genus
Lomaria. Although Mueller spelt the name
Lomaria fullageri, using an
e in the epithet, he referred to the surname "Fullagar". In 1905,
Carl Christensen transferred the species to
Blechnum, spelling the epithet
fullagari. The spelling
fullagarii is found in some sources; Article 60.8 of the
International Code of Nomenclature for algae, fungi, and plants only allows the use of a single "i" with names ending in "er" not "ar". In 2016,
André Luís de Gasper and
Vinícius Antonio de Oliveira Dittrich transferred the species to
Cranfillia as
Cranfillia fullagari. ==Distribution and habitat==