THE POLYSTICHUM HOMEPAGE
This map of world diversity is a work in progress at the University of Vermont. The map is based on a complete tally of all known species names in the genus Polystichum, reviewed with reference to floristic works from each region in the world. The numbers are obviously approximate in many places. The best-known centers are Australia-New Zealand, NW North America, Africa, and Mexico. The most work is needed in Brazil and the Philippines
A Portrait of the genus Polystichum
Geography and Diversity of Polystichum (The Map)
Research on Tropical American Polystichum at the University of Vermont
This map in a more densely illustrated and annotated form was presented as a poster at the Polystichum minisymposium at Kew Gardens in November of 2005. PDF of Kew Poster. Details on methodology, lists of species, and any other information are generally available on request from Dave Barrington.