A Key To Tree Leaves in Illinois

1. Leaves opposite ......................................................... 2
1. Leaves alternate ........................................................ 7
2. Leaves simple ........................................................... 3
2. Leaves compound ..........................................................34
3. Leaves lobed ............................................................. 4
3. Leaves unlobed, veins parallel to margin ..................Flowering Dogwood
4. Margins of the lobes not repeatedly toothed ...............................5
4. Margins of the lobes definitely and sharply toothed..............Silver Maple
5. Edges of the leaf not toothed, lobes come to a droopy point.......Black Maple
5. Edges of the leaf somewhat toothed or wavy.................................6
6. Leaf broad, base of leaf is straight, dark green.....................Sugar Maple
6. Edges of the leaf sparsely toothed, leaf broud, pale green.............Red Maple
7. Leaves Simple..............................................................8
7. Leaves Compound...........................................................36
8. Leaves bristle-tipped.....................................................9
8. Leaves not bristle-tipped................................................13
9. Leaves Lobed............................................................10
9. Leaves Unlobed..........................................................17
10. Sinuses deep, extending almost to midline of leaf......................11
10. Sinuses not as deep....................................................18
11. Leaves smooth (not furry) underneath...................................12
11. Leaves somewhat furry below, petiole long and yellow...............Black Oak
12. Leaves 5 to 8 inches long, 7-9 lobes.............................Shumard Oak
12. Leaves 3 to 5 inches long, usually 5 lobes..........................Pin Oak
13. Leaves Lobed............................................................14
13. Leaves Unlobed............................................................19
14. Margins definitely toothed...............................................15
14. Margins not toothed.......................................................27
15. Leaves star-shaped with 5 palmate lobes............................Sweet gum
15. Leaves not palmately lobed...............................................16
16. Leaves have irregular lobes, blueish green.......................Red Mulberry
16. Leaves with 3-5 coursely toothed main lobes, yellowish green.........Sycamore
17. Leaves 2-5 inches long, lance shaped................................Willow Oak
17. Leaves 4-6 inches long, also lance shaped...........................Shingle Oak
18. Has 7-11 lobes.................................................Northern Red Oak
18. Has 5-7 lobes, petiole long and yellow..............................Black Oak
19. Leaf margins toothed or wavy.........................................20
19. Leave margins not toothed.............................................30
20. Leaf triangular with a broud straight base, petiole flattened........Cottonwood
20. Leaf not as above..........................................................21
21. Leaves heartshaped, blueish green, rough surface....................Red Mulberry
21. Leaf surface smooth.......................................................22
22. Leaves in bunches, toothed margins, lance shaped......................Possumhaw
22. Leaves not as above....................................................23
23. Leaf margins wavy to almost lobed, veins prominent.....................Witch Hazel
23. Leaf margins have sharply pointed teeth....................................24
24. Base of leaf lopsided......................................................25
24. Base of leaf even on both sides ...........................................32
25. Leaf very broad and heart shaped, leaves large............................Basswood
25. Leave narrow and lance shaped.........................................26
26. Leaf margin coarsely toothed........................................American Elm
26. Leaf margin toothed, except base is smooth............................Hackberry
27. Leaves have 4 main lobes, two top lobes form a broad notch.............Tulip Tree
27. Leaf not as above......................................................28
28. Leaves have 2 or 3 pointed lobes; spicy odor when crushed............Sassafras
28. Leaves with more than 3 lobes...........................................29
29. 5-7 Lobes with deep sinuses, blades broader at upper end................Bur Oak
29. Rounded lobes, sinuses often shallow, varies widely on trees.............White Oak
30. Leaves heart shaped...................................................Red Bud
30. Leaves not heart shpaed.................................................31
31. Leaves lance-shaped, base lopsided...................................Sugarberry
31. Leaves egg-shaped, 6-12 inches long....................................Paw Paw
32. Leaves narrow and long, margins finely toothed...................Wild Black Cherry
32. Leaves egg shaped, coarsely toothed..........................................33
33. Leaf base wedge shaped, leaf nearly triangular.......................River Birch
33. Leaf more rounded at base.............................................Hop Hornbeam
34. Leaves pinnately compound.................................................35
34. Leaves palmately compound............................................Buckeye
35. 3-5 Leaflets, irregularly toothed...................................Box Elder
35. 7-11 Leaflets.................................................White or Green Ash
36. 7-30 leaflets.............................................Honey or Black Locust
36. Fewer than 11 leaflets..............................................Bitternut Hickory