Leaves broad and flat, never needle-like or scale-like; leaves simple,
alternate, lobed.
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_