Ash, a genus of trees that shed the leaves in the winter, have imperfect flowers, and a seed-vessel prolonged into a thin wing at the apex. There are many species, chiefly indigenous to Europe and North America. The ash is one of the most useful trees, on account of its hard, tough wood and the rapidity of its growth. There are many varieties of it, as the weeping ash, the curled-leaved ash and the entire-leaved ash. The flowering, or manna-ash, is a native of the south of Europe and Palestine. It yields the substance called manna, which is obtained by making incisions in the bark, when the juice exudes and hardens. Among the American species are the valuable white ash, with lighter bark and leaves; the red or black ash, with a brown bark; the black ash, and the blue ash. Several species not properly of this genus are popularly called ash. See MOUNTAIN ASH; PRICKLY ASH.