Price's Potato-bean

Apios priceana

Description

Price's potato-bean (Apios priceana ) is a perennial twining vine that grows from a large tuber to a height of 15 ft (4.5 m) . The alternate leaves are pinnately compound and consist of five to seven leaflets, which are ovate-lanceolate to ovate in shape. The flowers, which are borne in clusters at the leaf axils, are greenish white, tinged with purplish pink. Individual flowers are about 0.8 in (2 cm) long. Plants flower from mid-June through August and bear fruits, which are cylindrical beans up to 8 in (20.3 cm) long, through September.

This species can be most easily distinguished from the more common groundnut (A. americana ) by its flower. The uppermost petal of the Price's potato-bean flower has a fleshy appendage at its tip and is yellow-green. The groundnut flower is purplish maroon and lacks the fleshy tip.

Habitat

Price's potato-bean grows in forest openings and along wood edges in well-drained soils. It is often found where bluffs descend to streams. Some populations also occur in disturbed areas such as roadside rights-of-way or powerline cuts.

Plants associated with Price's potato-bean include Quercus muhlenbergii, Lindera benzoin, tall bell-flower (Campanula americana ), cane (Arundinaria gigantea ), basswood (Tilia americana ), white ash (Fraxinus americana ), sugar maple (Acer saccharum ), slippery elm (Ulmus rubra ), redbud (Cercis canadensis ), and Virginia creeper (Parthenocissus quinquefolius ).

Distribution

This species was first collected in 1896 from Warren County, Kentucky. It has been documented from 21 sites in five states: Illinois, Kentucky, Tennessee, Alabama, and Mississippi.

Of the 21 historic populations only 13 exist today. The species is no longer found at the Illinois site, which is in a national forest, or in Warren County, Kentucky, where it was first collected. Currently there are four populations in Mississippi and three each in Tennessee, Kentucky, and Alabama. Only five populations consist of more than 50 plants.

The Mississippi populations occur in the northeastern part of the state in Oktibbeha, Clay, and Lee counties. In Oktibbeha County there are two populations of between 50 and 80 plants each. In Clay County there is a single population of between 15 and 20 plants. The Lee County population is the largest in the state with several hundred plants on an acre of privately owned land.

In Tennessee, Price's potato-bean is known from sites in three counties. The largest population is in Marion County, where hundreds of plants are scattered on a bluff near a road. A population of between 20 and 30 plants occurs along a creek in Montgomery County. The third site, in Williamson County, supports only two plants.

Populations in Kentucky are found in the western counties of Livingston, Trigg, and Lyon. The Livingston County population, which in 1984 consisted of between 50 and 65 plants, has recently been severely reduced by cattle grazing and trampling. The Lyon County site supports a population of between 25 and 30 plants, while the Trigg County site supports only a few plants.

In Alabama there are three known sites of Price's potato-bean. Populations of between 15 and 30 plants occur in Madison and Autauga counties. A site in Marshall County supports less than five plants.

Threats

Price's potato-bean has undergone a major decline in recent years as almost half of the known populations have disappeared. The species was never common and the loss of plants is attributed to cattle grazing and trampling, clear-cutting, natural succession, and the application of herbicides to maintain rights-of-way.

Most of the remaining populations occur on privately owned land and lack adequate protection. Only two sites are on federal land. The Trigg County, Kentucky, site, which contains only a few plants, is on Tennessee Valley Authority land in an area designated as a Conservation Education Center. The Autauga County, Alabama, site, which has 15-30 plants, is on land administered by the Army Corps of Engineers. The Nature Conservancy owns and protects the Montgomery County, Tennessee, site, which supports 20-30 plants.

Conservation and Recovery

The voluntary cooperation of landowners is necessary to prevent destruction of remaining populations through clear-cutting or the introduction of cattle. Where Price's potato-bean occurs along powerline cuts and roadside fights-of-way, the U. S. Fish and Wildlife Service is working with the responsible agencies to plan maintenance and construction activities. Since Price's potato-bean is native to forest openings, it is also threatened by natural succession. Four populations are declining because of the closing of the forest canopy and competition from plants that are adapted to such conditions. Selective cutting at some sites might be necessary to save populations.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

U. S. Fish and Wildlife Service
6578 Dogwood View Parkway, Suite A
Jackson, Mississippi 39213

References

Kentucky Nature Preserves Commission. 1982."Summary Status Report on Apios priceana in Kentucky." Unpublished report.

Kral, R. 1983. A Report on Some Rare, Threatened, or Endangered Forest-related Vascular Plants of the South. USDA, Forest Service, Technical Publication R8-TP2.

Medley, M. E. 1980. "Status Report of Apios priceana." U.S. Fish and Wildlife Service, Atlanta, Georgia.

Seabrook, J. A., and L. A. Dionne. 1976. "Studies in the Genus Apios. I. Chromosome Number and Distribution of Apios americana and A. priceana." Canadian Journal of Botany 54:2567-2572.

Woods, M. 1988. "A Revision of Apios and Cochlianthus (Leguminosae)." Ph.D diss. Southern Illinois University, Carbondale.