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DescriptionThis small tree is up to 30' tall, forming either a single or multiple trunks (usually the latter) up to 1' across. There is a narrow crown around each trunk. Trunk bark is white to light gray with horizontal fissures; it does not peel away. There are also flattened arrowhead markings that are black from detached branches. Branch bark is black to gray, while twigs are reddish brown with white lenticels. Young shoots are light green and usually pubescent. Either opposite or alternate leaves develop along the twigs and young shoots. The leaf blades are up to 3" long and 2" across; they are deltate in shape and doubly serrated along their their margins. The bases of these blades are broadly obtuse, while their tips are elongated and slowly tapering. The upper blade surface is medium green and glabrous, while the lower surface is pale green and glabrous. The petioles are light green to pale reddish green and somewhat flattened; they are up to 1½" long. Gray Birch is monoecious, producing separate male (staminate) and female (pistillate) catkins on the same tree. Drooping male catkins up to 3" long occur individually at the tips of twigs. Each male catkin consists of numerous male florets and floral bracts. Each male floret has 2 stamens, an insignificant calyx, and no corolla; male florets occur in groups of 3 behind floral bracts that are cordate-orbicular in shape. Erect female catkins about 1/3" long occur among the new leaves of twigs. Each female catkin consists of numerous female florets and floral bracts. Each female floret consists of a somewhat flattened ovary with a pair of styles at its apex; female florets occur in groups of 2-3 behind floral bracts that are 3-lobed. The blooming period occurs from late spring to early summer and lasts about 1-2 weeks. Afterwards, female catkins become about 2/3" long and droop downward as they mature. The samaras (winged seeds) are distributed by the wind during late autumn or winter. The seed bodies of the samaras are ellipsoid to obovoid and somewhat flattened. Each samara has a pair of membranous wings that are more wide than the seed body. The root system is shallow and branching.