[Illustration: FIG. 81.--Bark of the Black Locust.]


CUCUMBER TREE (_Magnolia acuminata_)

Distinguishing characters: The *buds* are _small_ and _slender_ compared
with those of the other magnolia trees and are _covered_ with small
silvery silky _hairs_. The *habit* of the tree is to form a straight
axis of great height with a symmetrical mass of branches, producing
a perfect monopodial crown. The tree is sometimes known as _mountain
magnolia_.


UMBRELLA TREE (_Magnolia tripetala_)

Distinguishing characters: The _buds_, Fig. 80, are extremely _long_,
often one and a half inches, have a _purple color_ and _are smooth_.
The tree does not grow to large size and produces an open spreading
head. Its leaves, twelve to eighteen inches long, are larger than
those of the other magnolia trees. The tree is sometimes called
_elkwood_.


BLACK LOCUST (_Robinia pseudacacia_)

Distinguishing characters: The *bark* of the trunk is _rough_ and
_deeply ridged_, as shown in Fig. 81. The *buds* are _hardly
noticeable_; the twigs sometimes bear small spines on one side. The
leaves are large, compound, and fern-like. The individual leaflets
are small and delicate.