Carpinus caroliniana


Article by Frank Dennis Bishop, Jr.

BOTANICAL NAME: Carpinus caroliniana

COMMON NAMES: American hornbeam, Blue Beech, Ironwood, Musclewood (Farrar, 1995)

HIGHER TAXA:

(Pedrides, 1988)

DESCRIPTION: The American hornbeam is a deciduous, spreading tree with branches that droop at the tips. It has a fluted gray trunk that has a muscular appearance (Brickell, 1989). The American hornbeam reaches a height of thirty feet with a spread between 15 and 20 feet. The tree is slow growing and short lived. The American hornbeam has light and informal growth with horizontal branching (Halfacret, 1979).

LANDSCAPE USE:

FOLIAGE:

BUDS:

BARK:

FLOWERS:

FRUIT:

IDENTIFICATION KEY: The American hornbeam was first described in 1785 as C.betulus var. virginiana by Humphrey Marshall. Three years later, Thomas Walter named the tree from South Carolina as Carpinus caroliniana. Winkler's 1904 monograph of the Betulaceae recognizes Carpinus caroliniana as only being found in North America. In 1935, Fernald recognized two varieties of C. caroliniana in the Eastern United States and Canada. The southeastern variety was called C. caroliniana caroliniana and the other variety found in northern deciduous forest regions was called C. caroliniana virginiana (Furlow, 1987). The American Hornbeamcan be identified from the other species of Carpinus because the fruit with bract irregularly and unequally trilobed to simple serrate (Huxley, 1992). Today, American hornbeam is recognized by its smooth, thin, unbroken, slate gray bark with muscle-like longitudinal ridges. The leaves of the American hornbeam are deciduous, alternate, simple, and arranged in two rows on the twig. The leaves are 5 to 10 cm long, becoming successively larger around the shoot. The upper surface of the leaf is bluish-green and yellowish-green beneath the leaf. The leaves also turn red in autumn. The veins are straight and parallel, each ending in a sharp tooth with at least two intervening teeth. The twigs are slender with a gray to reddish-brown color. The American hornbeam also has pollen flowers and seed flowers in separate clusters on the same tree. The pollen flowers are in dropping catkins that are 25 to 40 mm long and grow laterally on the previous year's twigs. The seed flowers are in elongated clusters at the tips of the new leafy shoots. Pollination occurs when the leaves begin to appear. The American hornbeam has ovoid, slightly hairy buds that are pressed up against the twig. The buds are reddish-brown with a whitish margin and they occur in four rows. The fruit of the American Hornbeam is a small, ovoid ribbed nut that is 6 to 9 mm long. (Farrar, 1995)

The New Royal Horticultural Society Dictionary of Gardening. (Key).

GEOGRAPHY:

Carpinus caroliniana L.

AREA STATUS REFERENCES
North America:
Continental United States; Canada
Yes Duncan & Duncan, 1988
Eastern North America:
United States east of Mississippi;
Ontario and eastern Canada
YesDuncan & Duncan, 1988
Southeastern United States:
AL AR DE DC FL GA KY MD NC SC TN VA WV
YesDuncan & Duncan, 1988
Southern Appalachian States:
AL GA KY MD NC SC TN VA WV
YesDuncan & Duncan, 1988
Coastal PlainLocalRadford, Ahles & Bell, 1968;
Jones & Coile, 1988
PiedmontLocalRadford, Ahles & Bell, 1968;
Jones & Coile, 1988
Blue Ridge MountainsLocalRadford, Ahles & Bell, 1968
Great Smoky Mountains National Park
LocalRadford, Ahles & Bell, 1968
Ridge and ValleyYesJones & Coile, 1988
Cumberland PlateauYesJones & Coile, 1988
Central ArchYesDuncan & Duncan, 1988
GeorgiaYesJones & Coile, 1988
Clarke County, GeorgiaYesUGA Herbarium Specimens
Sams FarmCommonFrank Bishop, Pers. Ob.
Old Field
No-
Wetland
YesFrank Bishop, Pers. Ob.
Woods
No-
1-Hectare Plot
No

NATURAL HISTORY: The American hornbeam is soil-tolerant. It needs medium drainage, moisture, and fertility. However, the American hornbeam has a very slow growth rate (Halfacret, 1979). The tree normally occurs on deep, rich, moist soils on the lower slopes in valleys and along the borders of streams and swamps. The American hornbeam is very shade tolerant. (Farrar, 1995) The tree normally grows in the shade of taller hardwoods. It is found in association with northern red oak, sweet gum, monkernut hickory, bur oak, sugar maple, and basswood. It also grows with smaller hop hornbeam, alder, redbud, and sumac. (Elias, 1980) The American hornbeam is known for its heavy, hard, tough and durable wood. The early settlers of America used it to make bowls and dishes because it is not subject to crack or leak. The tree was also used as fuel and its fruit used as food for animals. The nuts are eaten by ruffed grouse, bobwhite, pheasant, and wild turkey. (NYSite West Side, www)

LOCALLY: The American hornbeam can be found at Sam's Farm along the creek, and at the Georgia Botanical Gardens on the Orange Trail near the river.

REFERENCES:
Brickell, Christopher ed. 1989. The American Horticultural Society Encyclopedia of
Garden Plants
. Macmillan Publishing Co. New York, NY. pg. 430.

Drayton, John. 1798. The Carolinian Florist. (Could have used but unavailable.)

Duncan, W.H. & M. B. Duncan. 1988. Trees of the Southeastern United States. The
University of Georgia Press. Athens, Ga. (ISBN 0-8203-0954-0). 322 pages.

Elias, Thomas. 1980. Trees of North America. Times Mirror Magazine. New York, NY. pg. 389.

Farrar, John L. 1995. Trees of the Northern United States and Canada. Iowa State
University Press. Ames, Iowa. pg.306.

Furlow, J. J. 1987. The Carpinus Caroliniana Complex in North America. Lawrence,
Kansas. pg. 416, 428-9.

Halfacret, R. G. & Anne R. Shawcroft. 1979. Landscape Plants of the Southeast. Sparks
Press. London. pg. 240.

Hooker & Jackson. 1895. Index Kewensis. "Caroliniana, Walt. Fl. Carol. 236 =
american". At the Clarendon Press. Oxford. (Could have been used but was not available).

Huxley, Anthony & Mark Griffiths ed. 1992. The New Royal Horticultural Society
Encyclopedia of Garden Plants
. Macmillan Press Limited. London. pg. 523-4.

Jones, S. B. & N. C. Coile. 1988. Distribution of the Vascular Flora of Georgia. Dept.
of Botany, University of Georgia, Athens, GA.

NYSite West Side. www.

Pedrides, George. 1988. A Field Guide to Eastern Trees. Houghton Mifflin Co. Boston, MA.

Radford, A. E., H. E. Ahles & C. R. Bell. 1968. Manual of the Vascular Flora of the
Carolinas. University of North Carolina Press. Chapel Hill, NC.

Stapf, O. 1930. Index Londinensis. "Nicholson, Woods & Forests i. 361 (1884)". At the
Clarendon Press. Oxford. (Could have been used but was not available).