Flora of North America
"FNA presents for the first time, in one published reference source, information on the names, taxonomic relationships, continent-wide distributions, and morphological characteristics of all plants native and naturalized found in North America north of Mexico. The Flora will appear in 30 volumes and will be available in print and on the Web." [from website] Includes links to other on-line floras and databases.Link to the published volumes.
Identification
North America