The plants included in this section, with the exception of the Larch, are evergreens. They are all lofty trees, with straight erect stems, and their branches growing in whorls or tiers, so as to produce a very peculiar and striking effect. The male and female catkins are on the same plant; the female one containing two seeds at the base of each scale. The pollen of the male flowers is so abundant that any one passing through a grove of these trees in May or June, might fancy it was raining brimstone. Most of the species are timber trees, producing the wood called deal; that used for the flooring and other parts of houses, being principally the wood of the Scotch Pine, and the Norway Spruce. Most of the species produce turpentine, which is the thin part of the sap which flows from the tree when a notch is cut in the trunk; the thick part of the sap when purified by boiling is the yellow resin. Tar is produced by cutting the roots and wood of pine and fir trees into pieces, and putting them into a sort of oven; when the tar runs from the charred wood, and lamp-black is made from the soot which collects on the roof of the oven. Pitch is boiled tar. Pyroligneous acid is obtained by burning the wood into charcoal in an iron cylinder, and condensing the vapour that arises from it. THE GENUS PINUS. [Illustration: FIG. 93.—BRANCH OF THE SCOTCH PINE.] [Illustration: FIG. 94.—CONE OF THE SCOTCH PINE (_Pinus sylvestris_).] This genus, according to Linnæus, was made to include all the Pines and Firs, the Cedar and the Larch; and this arrangement has been followed by the late A. B. Lambert, Esq., in his magnificent work on this tribe. In its present restricted form, it contains only those plants that have long slender leaves, which are produced in membranaceous sheaths, (see _a_ in _fig._ 93) two, three, or five together. The male flowers are produced in long upright catkins, (_m_) growing two or three together, and they consist each of one scale, which is surmounted by a kind of crest, (_b_). The pollen is contained in two cells formed in the body of each scale, which open lengthways, as shown in the scale of the Scotch Pine (_Pinus sylvestris_), at (_g_) in _fig._ 94. The female scales or carpels when ripe form a strobile or cone (_d_), and in the Scotch Pine they are thickened at the tip (_e_ in _fig._ 93); but when young they appear as shown at (_f_). Each scale is furnished with a thin membrane-like bract on the outside, which is conspicuous when young, but which is hidden by the scales in the ripe cone; and each has two seeds inside, which are each furnished with a long thin transparent wing (_c_). When the seed is ripe, the cone opens as shown at (_d_), and the seeds falling out are carried away by the wind. When the seed is sown and begins to germinate, the young plant sends down a root, and pushes through the ground its upright shoot, which has six cotyledons, bearing the husk of the seed upon their tip. All the species of the