The PA Flora Database (PFD) has its roots in the work of Edgar Wherry, John Fogg, Jr., and Herbert Wahl, the "Atlas of the Flora of PA", pub. by the Morris Arboretum of the Univ. of PA. Over a period of 40 years, Wherry and his colleagues gathered data from the major PA herbaria and manually placed a quarter of a million dots on over 3,500 maps, which are reproduced in this volume. The checklist of included taxa has undergone extensive review to reflect recent taxonomic and nomenclatural revisions. Recent discoveries have been added and distribution data has been updated. This volume also includes collections made in the 1990s in conjunction with the PA Natural Diversity Inventory. Extensive illustrations. Reprinted 1996.
