[Illustration:  FIG. 9.—­Twig of the Norway Spruce.]

HEMLOCK (Tsuga canadensis)

Distinguishing characters:  Its leaves are arranged in flat layers,
    giving a flat, horizontal and graceful appearance to the whole
    branch (Fig. 8).  The individual leaves are dark green above, lighter
    colored below, and are marked by two white lines on the under side
    (Fig. 10).

    The leaves are arranged on little stalks, a characteristic that does
    not appear in the other evergreen trees.

Form and size:  A large tree with a broad-based pyramidal head, and a
    trunk conspicuously tapering toward the apex.  The branches extend
    almost to the ground.

Range:  The hemlock is a northern tree, growing in Canada and the United
    States.

Soil and location:  Grows on all sorts of soils, in the deepest woods as
    well as on high mountain slopes.

Enemies:  None of importance.

Value for planting:  The hemlock makes an excellent hedge because it
    retains its lowest branches and will stand shearing.  In this respect
    it is preferable to the spruce.  It makes a fair tree for the lawn
    and is especially desirable for underplanting in woodlands, where
    the shade from the surrounding trees is heavy.  In this respect it is
    like the beech.

Commercial value:  The wood is soft, brittle, and coarse-grained, and is
    therefore used mainly for coarse lumber.  Its bark is so rich in
    tannin that it forms one of the chief commercial products of the
    tree.

Other characters:  The fruit is a small cone about 3/4 of an inch long,
    which generally hangs on the tree all winter.

[Illustration:  FIG. 10.—­Twig of the Hemlock.]

GROUP III.  THE RED CEDAR AND ARBOR-VITAE

How to tell them from other trees:  The red cedar (juniper) and
    arbor-vitae may be told from other trees by their leaves, which
    remain on the tree and keep green throughout the entire year.  These
    leaves differ from those of the other evergreens in being much
    shorter and of a distinctive shape as shown in Figs. 12 and 13.  The
    trees themselves are much smaller than the other evergreens
    enumerated in this book.  Altogether, there are thirty-five species
    of juniper recognized and four of arbor-vitae.  The junipers are
    widely distributed over the northern hemisphere, from the Arctic
    region down to Mexico in the New World, and in northern Africa,
    China, and Japan in the Old World.  The arbor-vitae is found in
    northeastern and northwestern America, China, and Japan.  The species
    mentioned here are those commonly found in America.