Common Trees of the North Carolina Piedmont

Stephen M. Seiberling, Alan S. Weakley, and Peter S. White

Carpinus caroliniana Walt. American hornbeam, blue beech, ironwood, musclewood. Synonyms Carpinus caroliniana ssp. caroliniana (Marsh.) Furlow, Carpinus caroliniana var.virginiana (Marsh.) Fern. Family Betulaceae. ITIS Taxonomic Serial Number 19504. USDA PLANTS Symbol CACA18. TROPICOS # 03600080.

Images • Branchlet with leaves. • Individual leaf. • Branchlet with leaf buds. • Close-up of leaf buds. • Branchlet with flower buds. • Close-up of flower buds. • Herbarium sheet 1. • Herbarium sheet 2.

Brief Description: A small, deciduous tree, usually ranging from 4–15 m (13–50 ft.) tall when fully grown. Bark of mature trunks is gray and smooth, sometimes roughened, often with a fluted or sinewy appearance. Leaves are alternate, elliptic to ovate or oblong-ovate in shape, usually with doubly serrate margins. Flowers are in catkins, with separate male and female catkins on the same tree. Fruits are small (4–9 mm long), brown or tan nuts, each pair of nuts subtended by a conspicuous, three-lobed, leafy bract. American hornbeam is typically an understory tree, most often found in bottomland forests, swamps, or along rivers and streams throughout much of the eastern United States. The sinewy appearance of the trunk accounts for one of its common names, musclewood.

Detailed Description:

Plant habit and life style. Plants Angiosperms, monoecious, 4–15(–20) m tall.

Stems. Pith continuous. Young twigs (1-year-old or less) green, glabrous or pubescent. Twigs (2–4 years old) glabrous or pubescent. Leaf scars crescent-shaped or half-round or oval, bundle scars 3 per leaf scar, stipule scars present, stipule scars not circumferential, short shoots present, short shoots bearing leaves. Bark of mature trunks furrowed or ridged or smooth.

Buds. Buds axillary, brown or reddish-brown, (2–)3–4(–6) mm long, conic or ovoid, sharp, pubescent, bud scales imbricate.

Leaves. Leaves deciduous, simple, petiolate, alternate or spiral, (1–)3–12 cm long, (0.8–)1–6 cm wide, elliptic or oblong or ovate, leaf margins serrate or serrulate or doubly serrate, leaf apices acuminate or acute or obtuse, leaf bases cordate or cuneate or oblique or obtuse or rounded. Leaf upper surface blue-green or green, glabrous or glabrate or pubescent. Leaf lower surface green or yellow-green, glabrous or glabrate or pubescent or with tufts in vein axils, puberulent. Leaf venation pinnate. Petioles (0.1–)0.6–0.9(–1.5) cm long, pubescent. Stipules present, caducous, blade-like, not circumferential.

Flowers. Flowering February or March or April. Inflorescences axillary or terminal, catkins, flowers sessile. Flowers unisexual or pistillate or staminate, epigynous. Perianth. Calyx radially symmetric, aposepalous. Sepals 1–6 per flower, ascending, sepal apices acute, persistent. Corolla absent. Androecium. Stamens 3(–6) per flower. Gynoecium. Ovaries inferior, pistils 1 per flower. Gynoecium syncarpous, 2 carpels per flower, styles 2 per pistil, placentation apical. Other floral features. Hypanthia present.

Fruits. Fruits nuts, 0.4–0.9 cm long, brown or green or tan, fruit maturation 1 years.

Habitat. Habitat bogs and seepages or bottomland forests or mesic upland forests or mixed forest edges or suburban plantings.

Special Diagnostic Characters. Fruit is subtended by a conspicuous, three-lobed, leafy bract.

Cite this publication as: ‘Stephen M. Seiberling, Alan S. Weakley, and Peter S. White (2005 onwards). Common Trees of the North Carolina Piedmont: Identification, Descriptions, Illustrations, and Glossary. Version: March 7, 2006. <>’.

Back to Contents