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.
Use of the guide
Trees can be identified by examination of several characteristics. The typical leaves of a species should be secured from mature trees, not young ones. The leaflets of a compound leaf can be distinguished from simple leaves by the absence of leaf buds from the base of their stems.
To identify a tree check one of the following characteristics, and if it is present then examine the characteristics at the next level of indentation. For example, if the tree has simple leaves then check whether the leaves alternate along stem or leaves are opposite along stem.
Simple leaves
Leaves alternate along stem
Margins entire
Oblong-ovate or obovate, large, thick: magnolia
Oblong, sub-evergreen at the south: sweetbay magnolia
Evergreen: rhododendron, kalmia
Obovate, 15-30 cm long: pawpaw
Oblong, thick, shining, 5-12 cm long: black tupelo
Oblong, tree occurring sparingly at the north: American persimmon
Heart-shaped: eastern redbud
Leaves of three forms; oval, two-lobed, or three-lobed; frequently all three on one spray: sassafras Thick, shining, willow-shaped: shingle oak, willow oak Thick, shining, ovate, spines in the axils: Osage-orange Broadly oval or obovate, veins prominent, leaves usually in clusters at the ends of the branches: pagoda dogwood Margins slightly indented Obliquely heart-shaped: linden Obliquely oval: elm Obliquely ovate: hackberry Oval or ovate, doubly serrate: birch (see Betula classification), American hornbeam Repand with spiny teeth: American holly Coarsely-toothed, twigs bearing thorns: black locust Of quivering habit, petioles compressed: poplar Long, slender, finely serrate: willow Coarsely crenately-toothed: chestnut oak Obovate or oval; wavy-toothed: witch-hazel Serrate: plum, cherry, crabapple, sourwood, juneberry, silverbell, beech Margins lobed Lobes entire Apex truncate, three-lobed: tulip tree Lobes and sinuses rounded: white oak Lobes rounded, lobes 2 or 3: sassafras Lobed or coarsely toothed, under surface covered with white down: white poplar Lobes slightly indented Five-lobed, finely serrate: American sweetgum Variously lobed, irregularly toothed: mulberry Lobes coarsely toothed Irregularly toothed, lobes bristle pointed: northern red oak Leaf broad, lobes coarsely toothed: American sycamore Leaves are opposite along stem Margins entire Ovate, veins prominent: flowering dogwood Heart-shaped, large: catalpa Oval: fringe tree Margins serrate: sweet viburnum, black haw viburnum Margins lobed: maple Compound leaves Leaves pinnately compound Alternate Margin of leaflets entire Leaflets oval, apex obtuse: black locust Leaflets oblong apex acute: poison sumac Leaflets oval or ovate: yellowwood (Cladrastis kentukea) Leaflets ovate — three in number: hoptree (Ptelea trifoliata) Margin of leaflets with two or three teeth at base: tree of heaven Margin of leaflets serrate: sumac, rowan, walnut, hickory Opposite Margin of leaflets entire: ash Margin of leaflets serrate: ash Margin of leaflets coarsely toothed: boxelder maple Leaves bi-pinnately compound Margins of leaflets entire: Kentucky coffeetree Irregularly bi-pinnate, margins of leaflets entire, thorns on stems above the axils of the leaves: honey locust Margins of leaflets serrate, stems spiny: prickly ash Leaves palmately compound: Ohio buckeye, common horse-chestnut
See also
Identification key
Leaf shape
External links
What Tree Is It? (OPLIN) Tree identification resources Tree Identification software for Kerala State, India - CD