PETERSON FIELD GUIDE TO WILDFLOWERS: Northeastern and North-Central North America by Margaret McKenny & Roger Tory Peterson

Grouped by color and by plant characteristics, 1,293 species in 84 families are described and illustrated. Included here are all the flowers you're most likely to encounter in the eastern and north-central U.S., westward to the Dakotas and southward to North Carolina and Arkansas, as well as the adjacent parts of Canada.