With the increased taxonomic stability and uniformity brought about by such authoritative synonymy, the entire flora of North America can now be viewed as a whole for comparison with the floras of other areas of the world. In all, more than 55,000 species of vascular plants in 255 families, are fully treated. All entries are arranged alphabetically by family, genus, species, subspecies, and variety and fully indexed to the generic level.Originally published in 1980. A UNC Press Enduring Edition -- UNC Press Enduring Editions use the latest in digital technology to make available again books from our distinguished backlist that were previously out of print. These editions are published unaltered from the original, and are presented in affordable paperback formats, bringing readers both historical and cultural value.