aflets 7 to 11,
lanceolate to oblong-lanceolate, serrate with deep teeth. Fruit
roundish-ovate, regularly separable only half-way, but friable at
maturity. Nut small, white, subglobose, with a very thin shell and an
extremely bitter kernel. Large tree with orange-yellow winter buds, and
firm, not scaly, bark. Wild throughout, and sometimes cultivated.

[Illustration: C. olivaeformis.]

7. =Carya olivaeformis=, Nutt. (PECAN-NUT.) Leaflets 13 to 15,
ovate-lanceolate, serrate; lateral ones nearly sessile and decidedly
curved. Fruit oblong, widest above the middle, with 4 distinct valves.
Nut oblong, 1 1/4 in., nearer smooth than the other edible Hickory-nuts,
the shell thin, but rather too hard to be broken by the fingers. The
kernel is full, sweet, and good. A tall tree, 80 to 90 ft. high. Indiana
and south; also cultivated, but not very successfully, as far north as
New York City.

ORDER =XXXIX. CUPULIFERAE.= (OAK FAMILY.)

This order contains more species of trees and shrubs in temperate
regions than any other, except the Coniferae. The genus Quercus (Oak)
alone contains about 20 species of trees in the region covered by this
work.

GENUS =83. BETULA.=

Trees or shrubs with simple, alternate, mostly straight-veined, thin,
usually serrate leaves. Flowers in catkins, opening in early spring, in
most cases before the leaves. Fruit a leafy-scaled catkin or cone,
hanging on till autumn. Twigs usually slender, the bark peeling off in
thin, tough layers, and having peculiar horizontal marks. Many species
have aromatic leaves and twigs.

* Trunks with chalky white bark. (=A.=)

=A.= Native. (=B.=)

=B.= Small tree with leafstalks about 1/2 as long as the blades 1.

=B.= Large tree; leafstalks about 1/3 as long as the blades 2.

=A.= Cultivated; from Europe; many varieties 3.

* Bark not chalky white, usually dark. (=C.=)

=C.= Leaves and bark very aromatic. (=D.=)

=D.= Bark of trunk yellowish and splitting into filmy layers 5.

=D.= Bark not splitting into filmy layers 4.

=C.= Leaves not very aromatic; bark brownish and loose and
shaggy on the main trunk; growing in or near the water 6.

[Illustration: B. populifolia.]

1. =Betula populifolia=, Ait. (AMERICAN WHITE OR GRAY BIRCH.) Leaves
triangular, very taper-pointed, and usually truncate or nearly so at the
broad base, irregularly twice-se