Wild Flowers of North Carolina: Also covering Virginia, South Carolina, and areas of Georgia, Tennessee, Kentucky, West Virginia, Maryland, and Delaware
My edition (1968) is a great resource. My only real complaint, and perhaps this has been rectified in later editions, is that the region in which the plant grows is not always specified.
Wildflowers of North Carolina: Also Covering Virginia, South Carolina, and Areas of Georgia, Tennessee, Kentucky, West Virginia, Maryland, and Delaware by William S. Justice, C. Ritchie Bell (University of North Carolina Press 1968) (582.13) catalogs the wildflowers of North Carolina and other states along the eastern seaboard. My rating: 7/10, finished 2010.