This manual is intended to facilitate the identification of vascular plants growing wild in the northeastern United States and adjacent Canada. The part of the United States covered extends from the Atlantic Ocean west to the western boundaries of Minnesota, Iowa, northern Missouri, and southern Illinois, south to the southern boundaries of Virginia, Kentucky, and Illinois, and south to the Missouri River in Missouri. In Canada the area covered includes Nova Scotia, Prince Edward Island, New Brunswick, and the parts of Quebec and Ontario lying south of the 47th parallel of latitude.