The leaves of all these different kinds of spruces vary greatly in length, thickness, and sharpness of point, according to the part of the tree on which they grow, and their surroundings. The shedding of the leaves on these or other spruces can be determined as easily as in the Norway spruce.
These three spruces like a cold climate and grow in many sections of the northern United States and Canada and farther south in the mountains. They are sometimes all found growing together, but the black spruce likes best the damp, cold swamps, while the others grow best on the drier and better drained lands. The black spruce is commonest. The red spruce is least known.
The Balsam Fir.
This is another evergreen tree which grows naturally in the cold, damp grounds of the northern United States and Canada, and to some extent in the eastern states as far south as West Virginia.
The foliage is borne in much the same manner as that of the spruces; yet there are interesting differences in the characters of these two kinds of leaves. Perhaps the most noticeable difference is in the shape; and the color of the fir leaves will attract our attention because the under side is a silvery color, while the upper side is green. What is the nature of the tip of the leaf and how does it compare with the pines and spruces in this respect? Does the leaf have a stem or petiole or is it attached directly to the branch without any stem? How are the leaves shed?
Fig. 242.—Black spruce. Half natural size.
The cones are about three inches long and present a rather delicate appearance. It will be interesting to determine the position of the cones, that is, the direction in which they point, and to learn whether it is the same when they are young as it is after they have matured.
The grayish colored bark of the trunk and limbs bears many "blisters" from which Canada balsam is obtained.