stration: C. Caroliniana.]

1. =Carpinus Caroliniana=, Walt. (AMERICAN HORNBEAM. BLUE OR WATER
BEECH.) Leaves ovate-oblong, pointed, sharply doubly serrate, soon
nearly smooth. Fruit with the scales obliquely halberd-shaped and
cut-toothed, 3/4 in. long, nuts 1/8 in. long. A tree or tall shrub, 10 to
25 ft. high, with a peculiarly ridged trunk; the close, smooth gray bark
and the leaves are much like those of the Beech. The wood is very hard
and whitish. Common along streams; sometimes cultivated.

[Illustration: C. Betulus.]

2. =Carpinus Betulus=, L. (EUROPEAN HORNBEAM.) This cultivated species
is quite similar to the American, but can be distinguished by the scales
of the fruit, which are wholly halberd-shaped, having the basal lobes
nearly equal in size, as shown in the cut; while the American species
has scales only half halberd-shaped.

GENUS =88. QUERCUS.=

Large trees to shrubs, with simple, alternate, deciduous or evergreen,
entire to deeply lobed leaves. The leaves are rather thick and woody,
and remain on the tree either all winter or at least until nearly all
other deciduous leaves have fallen. Flowers insignificant; the staminate
ones in catkins; blooming in spring. Fruit an acorn, which in the White,
Chestnut, and Live Oaks matures the same year the blossoms appear; while
in the Red, Black, and Willow Oaks the acorns mature the second year.
They remain on the tree until late in autumn. The Oaks, because of their
large tap-roots, can be transplanted only when small. Most of the
species are in cultivation. The species are very closely related, and a
number of them quite readily hybridize; this is especially true of those
of a particular group, as the White Oaks, Black Oaks, etc.

There is no attempt in the Key to characterize the hybrids, of which
some are quite extensively distributed. _Quercus heterophylla_, Michx.
(Bartram's Oak), supposed to be a hybrid between _Quercus Phellos_ and
_Quercus rubra_, is found quite frequently from Staten Island southward
to North Carolina.

* Cultivated Oaks from the Old World; bark rough; leaves more or
less sinuated or lobed. (=A.=)

=A.= Acorn cup not bristly 20.

=A.= Acorn cup more or less bristly 21.

* Wild species, occasionally cultivated. (=B.=)

=B.= Leaves entire or almost entire, or merely 3- (rarely 5-)
lobed at the enlarged summit. (=C.=)

=C