This genus, which includes all the Silver Firs, is readily distinguished from Abies by its leaves, which grow in two rows, one on each side the branch; thus the branch lies quite flat when placed on a table, or any other level surface. The leaves are also not the same on both sides as in the Spruce Firs, but the under side is marked by two distinct lines of silvery white, one on each side the midrib. The cones stand erect, and the dorsal bract is frequently so large as to appear above the tips of the scales; and the scales themselves are deciduous, falling off when the seeds are ripe, leaving the central rachis bare. This last peculiarity is very striking; as both the Pines and Spruce Firs retain the scales of their cones after the seeds have fallen. The seeds of the Silver Firs are much larger than those of the Spruces; and they are not attached to the wing in the same manner. The Silver Fir is a noble tree, and takes its name from the epidermis of its bark; which in young trees is of a whitish grey, and smooth, though when the tree is about fifty or sixty years old, it cracks and peels off, leaving the dark brown rough bark beneath. The cones are produced two or more together; they are upright and cylindrical, being nearly as large at both ends as in the middle. The leaves all curve upwards at the point, thus showing conspicuously the white lines on the under side. A remarkable circumstance connected with this tree is, that when it is cut down, the stump will remain alive for many years, and even increase considerably in size, without producing any leaves or branches. One in the forests of the Jura, which was ascertained to have lived ninety-two years after the tree had been cut down, had completely covered the section of the wood with bark. Strasburgh turpentine is produced from this tree. There are several species of this genus, some of which, as for example, _Picea Webbiana_, do not show the dorsal bract; while others, as _P. nobilis_, and _P. bracteata_, have it so large as to make the cone appear quite shaggy. All the species abound in resin, which frequently exudes from the cones. This genus is called Abies by Professor Link, and the German botanists. THE GENUS LARIX.—THE LARCH.