The American Hornbeam (Carpinus caroliniana) is a small hardwood tree in the genus Carpinus. American Hornbeam is also occasionally known as blue-beech, ironwood, or musclewood. It is native to eastern North America, from Minnesota and southern Ontario east to Maine, and south to eastern Texas and northern Florida.

It is a small tree reaching heights of 10-15 m, rarely 20 m, and often has a fluted and crooked trunk. The bark is smooth and greenish-grey, becoming shallowly fissured in old trees. The leaves are alternate, 3-12 cm long, with prominent veins giving a distinctive corrugated texture, and a serrated margin. The male and female catkins appear in spring at the same time as the leaves. The fruit is a small 7-8 mm long nut, partially surrounded by a three- to seven-pointed leafy involucre 2-3 cm long; it matures in autumn. The seeds often do not germinate till the spring of the second year after maturating.

There are two subspecies, which intergrade extensively where they meet:

• Carpinus caroliniana subsp. caroliniana. Atlantic coastal plain north to Delaware, and lower Mississippi Valley west to eastern Texas. Leaves mostly smaller, 3-9 cm long, and relatively broader, 3-6 cm broad.
• Carpinus caroliniana subsp. virginiana. Appalachian Mountains and west to Minnesota and south to Arkansas. Leaves mostly larger, 8-12 cm long, and relatively narrower, 3.5-6 cm broad.

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