23. Inner bark mucilaginous (“slippery” when chewed), leaves rough above, downy below red or slippery elm [220] 23. Inner bark not mucilaginous, leaves rather smooth above and downy below white or American elm [221]
24. Leaves 1 to 2½ inches long, rather blunt tips, flowers in fall cedar elm [222] 24. Leaves 1½ to 3 inches long, tapering point, flowers in spring winged elm (rare) [223]
25. Bark of trunk with warty or knotty projections rough-leaved hackberry [224] 25. Bark of trunk without warty projections [26]
26. Leaf length more than 4 times width peach [239] 26. Leaf length less than 3 times width [27]
27. Larger twigs with whitish cross-streaks, flowers and fruit in catkin-like racemes wild cherry (rare) [236] 27. Twigs without whitish cross-streaks, flowers and fruits not in racemes [28]
28. Lowest pair of primary leaf veins much longer than others New Jersey tea [260] 28. Lowest pair of primary leaf veins not much, if any, longer than others [29]
29. Leaf veins and midrib yellowish and prominent on under side, primary veins closely and evenly spaced Indian cherry [259] 29. Leaf veins and midrib not yellowish, if prominent on under side not closely and evenly spaced [30]
30. Leaves 3 to 5 inches long (rarely much larger), sometimes mitten-shaped or, on young shoots, intricately lobed, margins rather coarsely serrate or toothed red mulberry [227] 30. Leaves 1 to 3½ inches long, margins finely serrate or crenate, not lobed [31]
31. Leaves 1 to 2 inches long, margins crenate, veinlets not conspicuous, twigs pale gray swamp holly [253] 31. Leaves 2 to 3½ inches long, margins serrate, veinlets netted and conspicuous below, twigs purplish or reddish [32]
32. Width of leaves more than half their length, flat, glands on leaf-stem dark wild plum (tree) [237] 32. Width of leaves less than half their length, tending to fold lengthwise, usually 2 bright red glands on leaf-stem near leaf dwarf plum [238]