Regional floras typically contain complete dichotomous keys for identification of trees and other plants to species (e.g. Manual of vascular plants of northeastern United States and adjacent Canada by Henry A. Gleason and Arthur Cronquist). The following guide originates from Our Native Trees and How to Identify Them by Harriet L. Keeler and applies to some flowering trees which are indigenous to the region extending from the Atlantic Ocean to the Rocky Mountains and from Canada to the northern boundaries of the southern states, together with a few well-known and naturalized foreign trees. This guide excludes conifers and is not an exhaustive list of all trees known to occur in the region.