Fir
2 of the 7 encyclopedias on this shelf carry an entry for Fir. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
the common name of a large number of coniferous trees, of a pyramidal form and elegant proportions. This name is often used in a sense coextensive with the widest sense of the word PINE (q. v.), and therefore so as to include a la large portion of the Pinaceæ (conifera), or at least the whole of the Linnæan genus Pinus. But the name fir is also often used in a more restricted signification, and the trees so designated are those forming the genus Abies of some authors, Abies and Picea of others, which the greater number of from Pinus. In the classification of botanists have now agreed in separating Lindley, all the firs are included in the genus Abies. The common silver fir, Abies picea, has erect cylindrical cones, 5-6 inches long, and two-rowed leaves, with two white lines upon the under side. It forms considerable woods upon the mountains of central Europe and of the N. of Asia, and attains a height of 150-180 feet, and an age of 300 years. The wood is white, contains little resin, is very soft and light, and is employed for the ordinary purposes of coopers, turners, and joiners, and in ship and house carpentry, also for making bandboxes, and for many fine purposes, especially for the sounding-boards of musical instruments. It yields the beautiful clear turpentine known as Strassburg turpentine. Very similar to the silver fir, but generally of much smaller size, and indeed seldom much above 40 feet in height, is the Balm-of-Gilead fir (Abies balsamea), a native of the United States, from Virginia to Canada. The wood is of little value, but the tree yields the Canada balsam. (See TURPENTINE.) The other important species of firs will be seen under their particular names.
Aiton's Encyclopedia (1910)
a coniferous, evergreen tree. The common fir grows from Maine to minnesota and northward. It also follows the mountains to Virginia. In the most northerly or arctic part of its range it becomes a prostrate shurb. The seeds and bark bear minute cells of resinous balsam, whence, among lumbermen, the tree goes by the name of balsam fir. The leaves have a prominent midrib on the whitened lower surface, and are so arranged that the spreading branchlets seem flattened. The tips of fir branches are chosen by the hunter for a camp bed. They are laid with regularity, almost on end, so that the soft tips only are exposed. There are numerous species. The fir is the commonest coniferous tree of the Black Forest and of Switzerland. It is a valuable timber for masts and for housebuilding. The magnificent forest trees of the Pacific coast--the pride of the American lumberman--are mostly firs. A staff of Washington fir upholds the British flag above Windsor castle. Another is said to carry the Japanese flag at Tokio. See Conifers