Part 3

1. Leafstalks with milky sap when broken. 2. Leafstalks and lower surface of leaf with long hairs _Broussonetia papyrifera_ 2. Leafstalks and lower surface of leaf smooth or with short hairs. 3. Lower leaf surface hairy between the veins _Morus rubra_ 3. Lower leaf surface smooth or hairy only on the veins _Morus alba_ 1. Leafstalks without milky sap when broken. 4. Twigs usually with sharp spines. 5. Leaves broadest at the middle or above the middle. 6. Leaves broadest at the middle; lower surface of leaf smooth except for a few tufts of hairs near the veins _Crataegus viridis_ 6. Leaves broadest above the middle; lower surface of leaf hairy throughout _Crataegus punctata_ 5. Leaves broadest below the middle. 7. Leaves hairy throughout on the lower surface. 8. Leaves mostly tapering to the base; fruit a crab apple _Malus ioensis_ 8. Leaves rounded at the base; fruit a hawthorn. 9. Fruit with pitted seeds; flowers appearing in late May and June _Crataegus calpodendron_ 9. Fruit without pitted seeds; flowers appearing in April or early May _Crataegus mollis_ 7. Leaves smooth on the lower surface or hairy only on the veins. 10. Leaves tapering to the base. 11. Leaves oval to ovate to broadly lance-shaped _Malus coronaria_ 11. Leaves narrowly oblong to narrowly elliptic _Malus angustifolia_ 10. Leaves rounded at the base. 12. Leaves blue-green; fruit spherical or nearly so _Crataegus pruinosa_ 12. Leaves green; fruit shaped like a little apple _Malus coronaria_ 4. Twigs without spines. 13. Leaves star-shaped _Liquidambar styraciflua_ 13. Leaves not star-shaped. 14. Leaves 4-lobed, smooth on both surfaces _Liriodendron tulipifera_ 14. Leaves more than 4-lobed, hairy on one or both surfaces. 15. Leaves palmately lobed and veined. 16. Leaves densely coated with white felt on the lower surface _Populus alba_ 16. Leaves without a coat of white felt on the lower surface _Platanus occidentalis_ 15. Leaves pinnately lobed and veined. 17. Lobes of leaf with bristle-tips. 18. Leaves broadest above the middle _Quercus marilandica_ 18. Leaves broadest at or below the middle. 19. Leaves hairy throughout on the lower surface. 20. Lower surface of leaves with gray hairs; base of leaf blade usually broadly rounded. 21. Leaves with 5-11 more or less equal lobes, the uppermost lobe not strongly curved _Quercus pagodaefolia_ 21. Leaves with 3-5 more or less unequal lobes, the uppermost lobes often strongly curved _Quercus falcata_ 20. Lower surface of leaves with rusty hairs; base of leaf blade not broadly rounded _Quercus velutina_ 19. Leaves smooth on the lower surface or hairy only next to the veins. 22. Leaves divided less than halfway to the middle. 23. Leafstalks hairy; buds hairy, gray _Quercus velutina_ 23. Leafstalks smooth; buds smooth, reddish-brown _Quercus rubra_ 22. Leaves divided more than halfway to the middle. 24. Leafstalks hairy; cup of acorn fringed around the edge _Quercus velutina_ 24. Leafstalks smooth; cup of acorn not fringed around the edge. 25. Lower surface of leaves with large tufts of hairs in the vein axils. 26. Cup of acorn saucer-shaped. 27. Cup of acorn up to ½ inch broad. _Quercus palustris_ 27. Cup of acorn more than ½ inch broad _Quercus shumardii_ 26. Cup of acorn top-shaped. 28. Cup of acorn enclosing about ⅓ the nut at most _Quercus shumardii_ 28. Cup of acorn enclosing more than one-third of the nut _Quercus ellipsoidalis_ 25. Lower surface of leaves smooth or with small tufts in hairs in the vein axils _Quercus coccinea_ 17. Lobes of leaf with round tips, not bristle-tipped. 29. Leaves smooth on the lower surface _Quercus alba_ 29. Leaves hairy on the lower surface. 30. Upper three lobes of leaf squarish, forming a cross; twigs hairy _Quercus stellata_ 30. Leaves without three squarish lobes at the upper end; twigs smooth or nearly so. 31. Edge of acorn cup with a fringe _Quercus macrocarpa_ 31. Edge of acorn cup not fringed _Quercus lyrata_

Key to Illinois Trees in Winter

1. Green leaves present during winter, needle-like or scale-like Group G 1. Green leaves absent during winter Group H

GROUP G

1. Leaves in clusters of 2 or more. 2. Leaves in clusters of 5 _Pinus strobus_ 2. Leaves in clusters of 2-3. 3. Leaves in clusters of 2. 4. Most or all the leaves less than 3 inches long, usually twisted. 5. Leaves up to 1½ inches long; sheath at base of leaves not longer than ⅛ inch _Pinus banksiana_ 5. Leaves 2-3 inches long; sheath at base of leaves at least ⅓ inch long _Pinus sylvestris_ 4. Most or all the leaves longer than 3 inches, rarely twisted. 6. Leaves mostly less than 5 inches long; cone-scale with a small spine _Pinus echinata_ 6. Leaves mostly more than 5 inches long; cone-scale without a spine _Pinus resinosa_ 3. Leaves in clusters of 3. 7. Leaves flexible, mostly less than 5 inches long; sheath at base of leaves about ¼ inch long _Pinus echinata_ 7. Leaves stiff, mostly more than 5 inches long; sheath at base of leaves about 1 inch long _Pinus taeda_ 1. Leaves solitary, of 2 types, some of them scale-like and about ⅛ inch long, some of them needle-like and up to ⅓ inch long _Juniperus virginiana_

GROUP H