2. Acer Linnaeus, Sp. Pl. 2: 1054. 1753.
枫属 feng shu
Trees or shrubs. Leaves mostly simple and palmately lobed or at least palmately veined, in a few species pinnately veined and entire or toothed, or pinnately or palmately 3-5-foliolate. Inflorescence corymbiform or umbelliform, sometimes racemose or large paniculate. Sepals (4 or)5, rarely 6. Petals (4 or)5, rarely 6, seldom absent. Stamens (4 or 5 or)8(or 10 or 12); filaments distinct. Carpels 2; ovules (1 or)2 per locule. Fruit a winged schizocarp, commonly a double samara, usually 1-seeded; embryo oily or starchy, radicle elongate, cotyledons 2, green, flat or plicate; endosperm absent. 2n = 26.
About 129 species: widespread in both temperate and tropical regions of N Africa, Asia, Europe, and Central and North America; 99 species (61 endemic, three introduced) in China.
Acer lanceolatum Molliard (Bull. Soc. Bot. France 50: 134. 1903), described from Guangxi, is an uncertain species and is therefore not accepted here. The type specimen, in Berlin (B), has been destroyed. Up to now, no additional specimens have been found that could help clarify the application of this name.
Worldwide, Japanese maples are famous for their autumn color, and there are over 400 cultivars. Also, many Chinese maple trees have beautiful autumn colors and have been cultivated widely in Chinese gardens, such as Acer buergerianum, A. davidii, A. duplicatoserratum, A. griseum, A. pictum, A. tataricum subsp. ginnala, A. triflorum, A. truncatum, and A. wilsonii. In winter, the snake-bark maples (A. davidii and its relatives) and paper-bark maple (A. griseum) are eye-catching. Maple wood is used for furniture, interior beams in buildings, and wooden tools. The young leaves of A. tataricum subsp. ginnala can be used as a substitute for tea.