Carya illinoinensis

(Wangenheim) K. Koch

by Brad W. Roehl

Carya illinoinensis

(The Pecan Tree)

I. Common Names:

pecan tree

II. Higher Taxa:

Class--

Dicotyledonae

Order--

Juglandales

Family--

Juglandaceae

Genus--

Carya

(Mabberley, 1987)

III. Identification:

Carya illinoinensis characterized by its compound leaves, which are12 to 20 inches in length. These are longer than any hickory; however, they are not as large as walnuts. The number of compound leaves range from "9 to 17, which as described as oblong, lanceolate, gracefully sickle-curved, upward and outward, finely double-toothed, 4 to 8 inches long, 1 1/2 inches wide, smooth and shiny on top, smooth below, and they are thinner than the walnut." The bark can be described as being ridged, not peeling. The fruit are arranged in clusters of 3 to 11, which are pointed at the apex. The fruit measures 1 to 2 1/2 inches in length. They have a thin husk, which split to the base when mature. The nuts are brownish in color, and are ellipsoid in shape (Dean, 1968).

Pecan Tree Bark

Photo by Brad W. Roehl

The pecan tree can grow up to 44 meters in height. The twigs are "tan to reddish brown, slender, and conspicuously scaly (FONAEC, 1997)." The terminal buds are "yellowish brown, oblong, 6 to 12 mm, hirsute, and scaly (FONAEC, 1997)." The bud scales are" valvate, and axillary buds are protected b bracteoles fused into hood (FONAEC, 1997)."

Photo by Brad W. Roehl

The Pecan Compound Leaf

Photo by Brad W. Roehl

IV. Geography:

The pecan tree is cultivated in Florida, Georiga, Alabama, and South Carolina as a commericial product. Most likely none of these are growing as native today. Dr. Mohr has reported some native. The pecan tree is fairly abundant (Dean, 1968). The pecan tree is native to Arkansas, Illinois, Indiana, Iowa, Kansas, Louisiana, Mississippi, Missouri, Oklahoma, Texas, and Mexico (FONAEC, 1997). Extensive cultivation and naturalization has made the interpretation of the natural range of Carya illinoinensis very hard to ascertain.

Carya illinoinensis Area Status References North America: Continental United States Yes Dean, Blanche Evans, 1961 Eastern North America: United States east of Mississippi; Ontario and eastern Canada Yes Brison, Fred R., 1986 Southeastern United States: AL, AR, DE, DC, FL, GA, KY, MD, NC, SC, TN, VA, WV Yes Brison, Fred R., 1986 Southern Appalachian States: AL, GA, KY, MD, NC, SC, TN, VA, WV Yes Dean, Blanche Evans, 1961 Coastal Plain Yes Jones & Coile, 1988 Piedmont Yes Jones & Coile, 1988 Blue Ridge Mountains Yes Jones & Coile, 1988 Ridge and Valley Yes Jones & Coile, 1988 Cumberland Plateau Yes Jones & Coile, 1988 Central Arch Yes Dean, Blanche Evans, 1961 Georgia Yes Jones & Coile, 1988 Clarke County, Georgia Yes Brad Roehl, personal obser. Sams Farm ? -- Old Field ? -- Wetland ? -- 1-Hectare Plot ? --

Pecan Tree's distribution for commercial use

Pecan tree's natural distribution

[NOTE: Information obtained from Brison, Fred (1986) and the Flora of North America Editorial Commitee (1997)]

V. Natural History:

The minimum seed-bearing age for Carya illinoensis is about 20 years while the maximum age is around 300 years. However, the optimum age is anywhere from 75 to 200 years. Various acids and hydroxides are used in the preplanting treatment to break seed dormancy. The most common method of planting is stratification in sand, peat, or loamy soil at a temperature range of 35 F to 45 F for 30 to 90 days. Planting can be done during the Spring or Fall. However, for Spring planting only the stratified seed should be used (Vines, 1960). The pecan tree flowers during the months of March to May, and the fruit ripen from September to October in clusters of 2 to 10 (Vines, 1960).

VI. How to Encounter:

To find a specimem of Carya illinoinensis, one doesn't need to look very hard because they are very common. However, you can find a specimen in Louisiana by following these directions. Just on the north side of Haile off of LA 143 at the edge of a church parking lot, you will find a specimen. The large tree in the parking lot has Tillandsia and Polypodium as epiphytes (Univerisity of Georgia Herbarium). Also, they are locally common there (Louisiana--Union Parish County). The pecan tree is also very common in rich river-bottom soils (Sargent, 1965).

VII. References:

Brison, Fred R. 1986. Pecan Culture. Capital Printing. Austin, Texas. Dean, Blanche Evans. 1988. Trees and Shrubs of the Southeast. Birmingham Auduban Society Press. Birmingham, AL. Flora of North America Editorial Committee. 1997. Flora of North America: North of Mexico Volume 3. Oxford University Press. New York, NY. Jones, S.B. & N.C. Coile. 1988. Distribution of the Vascular Flora of Georgia. Dept. of Botany, University of Georgia. Athens, GA Mabberley, D.J. 1987. The Plant Book. Cambridge University Press. Sargent, Charles Sprague. 1965. Manual of the Trees of North America Volume 1. Dover Publications Inc.. New York, NY University of Georgia Herbarium Vines, Robert A. 1960. Trees, Shrubs, and Woody Vines of the Southeast. University of Texas Press.