Carolina Nature

Trees, Shrubs, and Woody Vines of North Carolina

American Hornbeam (Carpinus caroliniana)

Plantae>Magnoliophyta>Magnoliopsida>Fagales>Betulaceae>Carpinus caroliniana Walter

American Hornbeam (Carpinus caroliniana)

American Hornbeam, usually called Ironwood in North Carolina, is a fairly common understory tree found mostly along streambanks. Both of the two recognized varieties occur in NC, the northern var. virginiana (Marshall) Fernald, and the southern var. caroliniana. They are quite similar and many of the trees in the overlap range (such as in Durham County) are intergrades. The one at left is var. virginiana.

Haywood Co. NC 5/9/08.

American Hornbeam (Carpinus caroliniana)

Durham, NC 5/17/08.

American Hornbeam (Carpinus caroliniana)

Durham, NC 5/17/08.

American Hornbeam (Carpinus caroliniana)

Infructescences with leafy bracts appear in mid-spring. The one at left is a typical var. caroliniana — the bracts of the infructescence are more rounded and with a few blunt teeth versus var. virginiana's sharp tips and more, sharper teeth.

Chapel Hill, NC 5/2/2009.

American Hornbeam (Carpinus caroliniana)

This one from the New River valley in Virginia looks closer to var. caroliniana.

Grayson Co., VA 5/31/2009.

American Hornbeam (Carpinus caroliniana)

The one at left and next two are typical var. virginiana — with sharp tips and more, sharper teeth.

Haywood Co., NC 6/13/2009.

American Hornbeam (Carpinus caroliniana)

Haywood Co., NC 6/13/2009.

American Hornbeam (Carpinus caroliniana)

Haywood Co., NC 6/13/2009.

American Hornbeam (Carpinus caroliniana)

Another typical var. caroliniana.

American Hornbeam (Carpinus caroliniana)

The leaves of var. caroliniana are slightly smaller and narrower, with a more acute apex, and smaller and blunter secondary teeth.

American Hornbeam (Carpinus caroliniana)

This is a typical var. virginiana, photographed in the mountains of Carroll Co., Virginia. The differences are subtle - note that this leaf is broader and more jaggedly toothed than the one above and the bracts are less rounded and more toothed.

Hophornbeam (Ostrya virginiana) has similar leaves but much rougher bark and hop-like fruit clusters.

American Hornbeam (Carpinus caroliniana)

Male flowers, in catkins, appear in early spring.

Durham County is in the intergrade zone between var. virginiana of the Mountains and var. caroliniana of the Coastal Plain. Though many specimens are intermediate, variety caroliniana is more common here; most specimens of virginiana are from the northern part of the county.

Durham Co., NC 3/24/07.

American Hornbeam (Carpinus caroliniana) bark

Bark of a large tree.

The smooth, muscular bark is unique, not similar to that of any other local tree.

Durham Co., NC 3/24/07.

American Hornbeam (Carpinus caroliniana) bark

Bark of the same large tree, further down the trunk.

Durham Co., NC 3/24/07.

American Hornbeam (Carpinus caroliniana) bark

Bark of a mature tree.

Orange Co., NC 4/4/09.

American Hornbeam (Carpinus caroliniana) bark

Orange Co., NC 4/4/09.

Bark of a large tree.

Durham Co., NC 4/11/09.

More information:
NC State
Trees of Alabama and the Southeast
University of Connecticut
Virginia Tech Dendrology

Recommended Tree, Shrub, and Woody Vine Identification Guides