Comparisons: The Scotch pine is apt to be confused with the Austrian pine (Pinus austriaca), because they both have two needles to each cluster. The needles of the Austrian pine, however, are much longer, coarser, straighter, and darker than those of the Scotch pine; [Fig. 1]. The form of the Austrian pine, too, is more symmetrical and compact.
Fig. 6.—Twig of the Scotch Pine.
The red pine (Pinus resinosa) is another tree that has two needles to each cluster, but these are much longer than those of the Scotch pine (five to six inches) and are straighter. The bark, which is reddish in color, also differentiates the red pine from the Austrian pine. The position of the cones on the red pine, which point outward and downward at maturity, will also help to distinguish this tree from the Scotch and the Austrian varieties.
[Group II. The Spruce and Hemlock]
How to tell them from other trees: The spruce and hemlock belong to the evergreen class and may be told from the other trees by their leaves. The characteristic leaves of the spruce are shown in Fig. 9; those of the hemlock in [Fig. 10]. These are much shorter than the needles of the pines but are longer than the leaves of the red cedar or arbor vitae. They are neither arranged in clusters like those of the larch, nor in feathery layers like those of the cypress. They adhere to the tree throughout the year, while the leaves of the larch and cypress shed in the fall.
The spruces are pyramidal-shaped trees, with tall and tapering trunks, thickly covered with branches, forming a compact crown. They are widely distributed throughout the cold and temperate regions of the northern hemisphere, where they often form thick forests over extended areas.
There are eighteen recognized species of spruce. The Norway spruce has been chosen as a type for this group because it is so commonly planted in the northeastern part of the United States.
The hemlock is represented by seven species, confined to temperate North America, Japan, and Central and Western China.