Hemlock Spruce , the common name of the tree abies Canadensis, of the order coniferoe, which is quite as frequently called hemlock simply. The hemlock spruces mainly differ from the spruces proper in having flat two-ranked leaves, and the cells of the anthers opening transversely instead of lengthwise; from the firs they differ in having persistent cones and in the wing of the seed remaining attached to it; while in the firs the scales fall from the axis of the cone and the seed separates from its wing. On account of these differences Carriere proposed to place the hemlock spruces in a separate genus, to which he gave the barbaric name tsuga ; botanists do not accept his views, and regard the firs (picea), the spruces (abies), and the hemlock spruces (tsuga) as subgenera of abies. The hemlock spruce is essentially a northern tree. Making its appearance in the southern states only on the mountain ranges, it increases in frequency toward the northern borders of the United States, where large forests of it are not rare, while in Canada it covers vast tracts often without the presence of any other species, and extends to the northernmost limits of arborescent vegetation, and across to the Pacific. It grows in almost every situation except in a very dry one.
The hemlock spruce is one of the finest of our native conifers, reaching the height of 60, 80, and not rarely 100 ft. ; when it occurs as a solitary specimen, it appears as a fine pyramid of verdure, being furnished from the ground to the top with long gracefully drooping branches; but when it grows in the forest the straight trunk is without branches for the greater part of its length. The smaller branches and twigs are very slender; the leaves, about half an inch long with very short petioles, spread horizontally in two directions, and appear as if in two rows. They are flat, dark green above, and glaucous beneath. The cones are about three fourths of an inch long, of a few scales, greenish when young, but turning brown with age, and placed at the ends of the pendent branches of the preceding year. The wood of the tree is coarse, splits irregularly, and when exposed to the weather decays rapidly; yet with all these disadvantages it affords a large share of the lumber of commerce, and as the white pine disappears hemlock lumber comes more and more into use.
It is stronger than white pine, and gives a better hold to nails, and for all work not exposed it is preferred to pine; for beams, rafters, roof sheathing, and all parts of a house to be covered over, hemlock lumber is largely consumed, as it is for a great deal of other rough work. The great economical value of the hemlock is in its bark, which is largely used for tanning leather, either alone or in conjunction with oak bark; large forests have been destroyed by stripping the bark from the trunks, which were left to decay. As an ornamental tree the hemlock is not excelled in beauty by any native or exotic conifer. As single specimens, in a screen, or in a hedge, it is unequalled. For an ornamental hedge it has the advantage over deciduous plants, as it retains its beauty at all seasons; and the manner in which it bears cutting is a sufficient refutation of the common but erroneous belief that plants which naturally grow to large trees are unfit for hedges. The hemlock may be raised from seeds, but nurserymen get their supplies from the forest; young seedlings a foot high are taken up and planted closely together under a temporary screen of brush to shade them; those which survive the first summer are then planted in nursery rows, and afterward may be removed with safety.
Hemlock gum, incorrectly so called, is a resinous exudation of the hemlock spruce. The tree while growing contains but little resinous juice; but when it begins to decay, resinous exudations in the form of nodules, from the size of a walnut to nearly that of a hen's egg, are found upon the surface. The bark and chips to which these nodules adhere are boiled in water and the melted resin dipped off. It has a limited use in the preparation of stimulating plasters. In some localities this resin is largely used by the young for chewing, and was formerly sold for this purpose; but at present the most approved "chewing gum" is made from pa-raffine. The young shoots and leaves afford a volatile oil by distillation, which has a local reputation as a rubefacient. It has been used to produce abortion, with fatal results to the mother. - The Indian hemlock spruce (A. Bru-noniana), from Nepaul, A. tsuga, from Japan, A. Mertensiana, A. Hookeriana, and A. Alber-tiana, from the N. W. coast, are species of hemlock spruce to be found in collections of rare evergreens.
Hemlock Spruce (Abies Canadensis).