Research projects, field primers and publications from the staff of The New York Botanical Garden's field research program. Systematic botany documents the locations, properties and uses of plants in an effort to understand their relationships. http://sciweb.nybg.org/science2/InstituteOfSystematicBotany.asp
Provides standardized information about the vascular plants, mosses, liverworts, hornworts, and lichens of the U.S. and its territories including images, classification and distribution maps. http://plants.usda.gov/