The maples may be told by their leaves of characteristic shape, but chiefly by their two-seeded fruit or "keys," the two wings of which spread differently in different species. The leaves of some species change in autumn from green to red and other brilliant colors. Those of other species change to yellow without trace of red. Sixty to seventy species have been distinguished, nine of which occur in North America. [p042] FOOTNOTES [Footnote 25: See Sycamore, page 65.] [Footnote 26: These notes apply to the American product.] [Footnote 27: Vermont, New York, and Michigan produce the larger portion of the about fifty million pounds of sugar and three million gallons of syrup annually manufactured in the United States. Third Annual Report of the Fisheries, Game, and Forestry Commissioners, New York, 1897, p. 308.] [Footnote 28: Sargent.] SUGAR MAPLE, HARD MAPLE. _Acer saccharum Marsh._ _Acer saccharinum Wang._ Nomenclature. (Sudworth.) Sugar Maple, Hard Maple (local and common names). Black Maple (Fla., Ky., N. C.). Sugar Tree (frequent). Rock Maple (Me., Vt., N. H., Conn., Mass., R. I., N. Y., Tenn., Ill., Mich., Ia., Kans., Wis., Minn.). Locality. Best development Maine to Minnesota; range extends southward to Florida and Texas. Features of Tree. Seventy to one hundred feet and more in height, one and one-half to four feet in diameter. The fruit or "maple-key" with wings less than right angles ripen in early autumn; one seed-cavity is usually empty. Foliage turns to brilliant reds and other colors later. Large impressive tree. Color, Appearance, or Grain of Wood. Heartwood brownish, sapwood lighter, close-grained, compact structure, occasional "curly," "blister," or "birdseye" effects. Structural Qualities of Wood. Tough, heavy, hard, strong, susceptible of good polish, wears evenly, not durable when exposed. Representative Uses of Wood. Furniture, shoe-lasts, piano-actions, wooden type for showbills, pegs, interior finish, flooring, ship-keels, vehicles, fuel, veneers, rails, etc. Weight of Seasoned Wood in Pounds per Cubic Foot. 43. Modulus of Elasticity. 2,070,000. Modulus of Rupture. 16,300. Remarks. Birdseye, blister, and to a less extent curly and landscape effects pronounced in this species. Saccharum refers to sugar manufactured from the sap. Hard maple is because of hardness of wood. [p043] SILVER MAPLE, SOFT MAPLE. _Acer saccharinum Linn._ _Acer dasycarpum Ehr._ Nomenclature. (Sudworth.) Silver Maple, Soft Maple (local and common names). Swamp Maple (W. Va., Md.). Water Maple (Pa., W. Va.). River Maple (Me., N. H., R. I., W. Va., Minn.). White Maple (Me., Vt., R. I., N. Y., N. J., Pa., W. Va., N. C, S. C., Ga., Fla., Ala., Miss., La., Ky., Mo., Ill., Ind., Kans., Nebr., Minn.). Locality. New Brunswick to Florida, westward intermittently to Dakota and Indian Territory. Best development in lower Ohio River basin. Features of Tree.