Brown University (BRU) (1048)
Duke University (DUKE) (5258)
Indiana University (IND) (5327)
Missouri Botanical Garden (MO) (13669)
New York Botanical Garden (NYBG) (182872)
University of Alaska (ALA) (8093)
University of Michigan (MICH) (17707)
The pteridoportal taxonomic thesaurus is based on the Checklist of Ferns and Lycophytes of the World, generously provided by Michael Hassler.