American hornbeam is a member of the birch family and one of the 35 species in the genus, which is found only in the Northern Hemisphere. It is also called blue-beech, ironwood, and muscle-wood. 

American hornbeam is a small, slow-growing, short-lived tree in the understory of eastern mixed-hardwood forests. It typically grows 20 to 40 feet tall and only grows about one foot per year. The short, often crooked, trunk is covered with a smooth slate gray bark that has a characteristically sinewy appearance, resembling the muscles of a flexed arm.