Carpinus caroliniana, the American hornbeam, is a small hardwood understory tree in the genus Carpinus. American hornbeam is also known as blue-beech, ironwood, musclewood and muscle beech for the distinctive sinewy, muscle-like appearance of its trunk. It is native to eastern North America, from Minnesota to southern Quebec, east to Maine, and south to eastern Texas and northern Florida. It occurs in shaded areas with moist soil, particularly near the banks of streams or rivers, and is often a natural understory species of the riverine and maritime forests of eastern temperate North America.