The fern collection of the Herbarium Hamburgense is assigned to the cryptogam section and contains about 50,000 specimens. It is rich in types and was an important basis for Prof. R. Sadebeck, former director of the Botanical Museum Hamburg, in his treatment of the ferns for Engler and Prantl's book "Natürliche Pflanzenfamilien" (“Natural plant families”). Important partial collections come from K. Prantl, K. Müller (Halensis), A. Dietrich and others.