A genus, Acer, of broad-leaved, deciduous trees including about 115 species in North America, Asia, Europe, and North Africa. This genus is characterized by simple, opposite, usually palmately lobed (rarely pinnate) leaves, generally inconspicuous flowers, and a fruit consisting of two long-winged samaras or keys. The winter buds have several overlapping scales, rarely only two. The most important commercial species is the sugar or rock maple (A. saccharum), called hard maple in the lumber market. This tree, attaining a height of 120 ft (37 m), grows in the eastern half of the United States and adjacent Canada. It can be recognized by its gray furrowed bark, sharp-pointed scaly winter buds, and symmetrical oval outline of the crown (illus. a).