13. Thorny vines greenbrier [204] 13. Thorny trees or shrubs [14]
14. Leaf margins entire (smooth) [17] 14. Leaf margins not entire, variously serrate or toothed [15]
15. Leaves either blunt at tip or shallowly lobed or cut, primary veins usually straight to margins, often doubly serrate red haws [232] 15. Leaves pointed at tip, serrate, not cut or lobed, veins united or curving near margins [16]
16. Leaf width more than half the length, leaf flat, glands, if present on leaf-stem near leaf, dark wild plum (tree) [237] 16. Leaf width less than half the length, tending to fold lengthwise, usually two bright red glands on leaf-stem near leaf dwarf plum [238]
17. Leaf smooth or glossy, tip pointed, juice of stem milky bois d’arc or Osage orange [226] 17. Leaf wooly on under side, especially when young, usually rather blunt at tip, juice of stem not milky wooly bumelia, chittam wood or gum elastic [272]
18. Leaves either lobed or coarsely toothed [33] 18. Leaves neither lobed nor coarsely toothed, sometimes doubly toothed [19]
19. Leaf margin serrate or crenate or doubly toothed [20] 19. Leaf margin smooth or wavy [47]
20. Vines rattan [261] 20. Not vines [21]
21. Leaf margins doubly toothed (large and small teeth) [22] 21. Leaf margins not doubly toothed [25]
22. Leaves 3 to 7 inches long, twigs not corky winged [23] 22. Leaves 1 to 3 inches long, twigs sometimes corky winged [24]