Form and size:  The locust is a medium-sized tree developing a slender
    straight trunk when grown alongside of others; see Fig. 82.

Range:  Canada and United States.

Soil and location:  The locust will grow on almost any soil except a wet,
    heavy one.  It requires plenty of light.

Enemies:  The locust borer has done serious damage to this tree.  The
    grubs of this insect burrow in the sapwood and kill the tree or make
    it unfit for commercial use.  The locust miner is a beetle which is
    now annually defoliating trees of this species in large numbers.

Value for planting:  It has little value for ornamental planting.

Commercial value:  Though short-lived, the locust grows very rapidly.  It
    is extremely durable in contact with the soil and possesses great
    strength.  It is therefore extensively grown for fence-posts and
    railroad ties.  Locust posts will last from fifteen to twenty years. 
    The wood is valuable for fuel.

[Illustration:  FIG. 82.—­Black Locust Trees.]

Other characters:  The flowers are showy pea-shaped panicles appearing
    in May and June.  The fruit is a small pod.

Other common names:  Yellow locust; common locust; locust.

Comparisons:  The honey locust (Gleditsia triacanthos) can be told
    from the black locust by the differences in their bark.  In the honey
    locust the bark is not ridged, has a sort of dark iron-gray color
    and is often covered with clusters of stout, sharp-pointed thorns as
    in Fig. 83.  The fruit is a large pod often remaining on the tree
    through the winter.  This tree has an ornamental, but no commercial
    value.

[Illustration:  FIG. 83.—­Bark of the Honey Locust.]

HARDY CATALPA (Catalpa speciosa)

Distinguishing characters:  The tree may be told by its fruit, which
    hang in long slender pods all winter.  The leaf-scars appear on the
    stem in whorls of three and rarely opposite each other.

Form and size:  The catalpa has a short, thick and twisted trunk with an
    irregular head.

Range:  Central and eastern United States.

[Illustration:  FIG. 84.—­Hardy Catalpa Trees.]

[Illustration:  FIG. 85.—­Bark of the Flowering Dogwood.]

Soil and location:  It grows naturally on low bottom-lands but will also
    do well in poor, dry soils.

Enemies:  Practically free from disease and insects.

Value for planting:  The catalpa grows very rapidly and is cultivated in
    parks for ornament and in groves for commercial purposes.  The hardy
    catalpa is preferable to the common catalpa for planting.

Commercial value:  The wood is extremely durable in contact with the soil
    and is consequently used for posts and railroad ties.