length. In New England it seldom grows to as large a size as the
other spruce trees.

It covers large areas in various parts of northern North America and
grows to its largest size in Manitoba. The black spruce has little
value as an ornamental tree.

The _Colorado blue spruce_ (_Picea parryana_ or _Picea pungens_)
which is commonly used as an ornamental tree on lawns and in parks,
can be told from the other spruces by its pale-blue or sage-green
color and its sharp-pointed, coarse-feeling twigs. Its small size
and sharp-pointed conical form are also characteristic.

It grows to a large size in Colorado and the Middle West. In the
Eastern States and in northern Europe where it is planted as an
ornamental tree, it is usually much smaller.

[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.