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.

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.

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

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.

Male catkins appear in early spring.

Durham Co., NC 3/24/07.

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

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.

Bark of a large tree.

Durham Co., NC 3/24/07.

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

Durham Co., NC 3/24/07.