Each of 9 major classification systems is briefly introduced, then the link given to a .pdf file or web site.
Cowardin's Wetlands and Deepwater Habitats (Cowardin et al. 1979)
Bailey's Ecoregions (Bailey 1976-1997)
National Marine Sanctuary Program Resources Classification (Salm and Clark 1984)
National Vegetation Classification System (FGDC 1997)
Society of American Foresters Forest Cover Types (Eyre 1980)
US Fish and Wildlife Service ESM 103, Habitat Evaluation Procedures (US FWS 1981)
Hydrogeomorphic (HGM) Classification for Wetlands (Brinson 1993)