Alnus hirsuta is a species of flowering plant in the family Betulaceae. It is a tree native to Japan, Korea, northern China, the Russian Far east, and eastern Siberia. It is closely related to grey alder Alnus incana, and has sometimes been treated as a subspecies of it Alnus incana subsp. hirsuta on the grounds that it hybridises freely with it when brought together in cultivation. It differs from grey alder in larger leaves and larger seed catkins.
Description It is a tree growing to tall, usually with a single, straight trunk, with grey bark. The leaves are green above, grey-green below, with coarsely double-toothed margins, long and broad.
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