1. Leaves compound, with blades divided into leaflets 2 1. Leaves simple, blades not divided into leaflets 7 2. Leaves with opposite arrangement on twigs 3 2. Leaves with alternate arrangement on twigs 4 3. Leaflets with rounded bases, conspicuously whitish below when fresh; seed end of samara thickened, wing terminal only White Ash 3. Leaflets with wedge-shaped bases, green below; wing terminal and extending about half the length of the seed Green Ash 4. Buds valvate; buds, fruits, and lower surface of leaflets covered with yellow glandular scales; fruit winged on upper half of husk suture, husk thin, shell thin, meat bitter Bitternut Hickory 4. Buds imbricate, composed of overlapping scales 5 5. Leaflets typically 5, glabrous except for a few hairs on rachis and midribs; bark shaggy Shagbark Hickory 5. Leaflets 7 6 6. Leaflets densely tomentose; bark tight, in diamond-shaped pattern; husk very thick, shell thick, meat sweet Mockernut Hickory 6. Leaflets usually glabrous; bark tight, in diamond-shaped pattern; husk moderately thick, shell thick, meat sweet, husk tardily dehiscent Pignut Hickory 7. Leaves essentially evergreen, large percentage staying on trees until bud expansion, dark green above, silky white pubescent below; flowers white, about 5 to 8 cm in diameter Sweetbay 7. Leaves typically deciduous, or trees retaining some dead leaves to bud expansion 8 8. Leaf margins entire 9 8. Leaf margins lobed or toothed 12 9. Leaves with rusty pubescence below, broadly obovate, leathery bases tapering to cordate or cuneate Blackjack Oak 9. Leaves essentially glabrous or with a few hairs in vein axils 10 10. Leaves shiny below, elliptic or rhombic to spatulate Laurel Oak 10. Leaves dull green below 11 11. Leaves elliptic to obovate, strongly veined with purple spots and discoloration in summer; fruit a drupe Black Tupelo 11. Leaves abruptly obovate, bases wedge-shaped, few lateral veins; fruit an acorn Water Oak 12. Leaf margins toothed 13 12. Leaf margins lobed 16 13. Margins indistinctly toothed, blades narrowly to broadly ovate, base unequal, apex long acuminate Sugarberry 13.