s and flowers in catkins.

1a. Leaflets 11-23; pith divided by partitions into chambers --2.

1b. Leaflets 5-11; pith not partitioned (Hickory) --3.

2a. Pith brown; bark with flat longitudinal ridges
=Butternut, Juglans cinerea.=

2b. Pith cream-color; bark of trunk without flat ridges
=Black Walnut, Juglans nigra.=

3a. Bark of the trunk essentially smooth, not deeply furrowed or shaggy
--4.

3b. Bark of the trunk deeply furrowed or shaggy --6.

4a. Leaflets glabrous beneath; buds greenish --5.

4b. Leaflets somewhat pubescent beneath; buds bright yellow
=Bitter Nut, Carya cordiformis.=

5a. Twigs hairy =Small-fruited Hickory, Carya microcarpa.=

5b. Twigs smooth =Pignut Hickory, Carya glabra.=

6a. Twigs and leaves both pubescent --7.

6b. Twigs nearly smooth; leaves smooth beneath
=Shag-bark Hickory, Carya ovata.=

7a. Twigs brownish; buds densely hairy
=Mocker-nut Hickory, Carya alba.=

7b. Twigs orange; buds very slightly hairy
=King-nut Hickory, Carya laciniosa.=

BETULACEAE, the Birch Family

Trees or shrubs with alternate simple leaves and inconspicuous
monoecious flowers, the staminate flowers in catkins, and the pistillate
in catkins or small clusters.

1a. Trees, with white or yellowish bark exfoliating in thin papery
plates or scales --2.

1b. Tree or shrub, with smooth, dark gray bark; trunk fluted with
prominent longitudinal ridges =Hornbeam, Carpinus caroliniana.=

1c. Trees or shrubs; the bark more or less roughened, but not
exfoliating; trunk not fluted --3.

2a. Bark white or chalky
=Paper Birch, Betula alba var. papyrifera.=

2b. Bark yellowish =Yellow Birch, Betula lutea.=

3a. Shrubs, with leaves 4 cm. long or less --4.

3b. Shrubs or trees, with leaves 5 cm. long or more --5.

4a. Twigs glandular-warty =Dwarf Birch, Betula glandulosa.=

4b. Twigs not glandular =Swamp Birch, Betula pumila.=

5a. Twigs and bark with the odor of wintergreen
=Sweet Birch, Betula lenta.=

5b. Twigs and bark without odor of winter