This tree is 40-80' tall, forming a single trunk up to 2½' across and a globoid to ovoid crown. The trunk bark of mature trees consists of gray ridges that are separated by narrow brown furrows; sometimes the ridges are interlacing. Branch bark is more smooth and gray, while twigs are greenish brown to brown with scattered white lenticels. Pairs of opposite leaves occur along the twigs. Individual leaves are 3-6' long and 3½-7' wide; they are palmately lobed (usually 5 lobes). Each lobe is rather broad at the base, tapering gradually to a pointed tip; there are usually 1-2 large pointed teeth on either side of each lobe. The upper leaf surface is medium to dark green, while the lower surface is slightly more pale; both surfaces are hairless. The slender petioles are light green to pale yellow, terete, and glabrous; they are as long as, or slightly longer than, the adjoining leaf blades. Norway Maple can be monoecious or dioecious, producing male (staminate) flowers and female (pistillate) flowers on either the same or separate trees. Both types of flowers are produced in umbel-like clusters spanning 2-3' across; each cluster consists of 10-30 flowers. The slender stalks of each corymb are green and either hairless or glandular-hairy. Individual male and female flowers span about 8 mm. (a little less than 1/3') across; each flower has 5 sepals, 5 petals, and a circular central disk that are greenish yellow. Male flowers have 8 fertile stamens, while female flowers have a green pistil with a pair of styles and 8 sterile stamens. Each pistil has a pair of basal wings. The blooming period occurs during mid-spring shortly before, or at the same time as, the unfolding of the leaves. Fertile pistillate flowers are replaced by pairs of samaras (seeds with elongated wings) that are 1½-2' long. The samaras are joined together at the base, forming an angle that is a little less than 180°. Each pair of samaras dangles from a slender pedicel. The samaras become mature during the fall and turn brown; they are distributed by the wind. The woody root system is shallow and widely branching. The deciduous leaves usually turn yellow in the fall.