American Chaffseed

Schwalbea americana

Description

The American chaffseed is a perennial member of the snapdragon family. This plant is an erect herb with unbranched stems or branched only at the base and grows to a height of 11.8-31.5 in (30-80 cm). It is densely pubescent. The leaves are alternate, lance-olate to elliptic, stalkless, 0.3-0.8 in (0.8-2 cm) long, and entire. The upper leaves are reduced to narrow bracts. The flowers are large, purplish-yellow and tubular. The flowers are borne singly on short stalks in the axils of the uppermost; reduced leaves form a many-flowered, spike-like raceme. The flowers have a high degree of bilateral symmetry elaborated for pollination by bees. The capsule is long and narrow and is enclosed in a loose-fitting sac-like structure that provides the basis for the common name. Flowering occurs from April to June in the South, and from June to mid-July in the North. Chaffseed fruits are long, narrow capsules enclosed in a sac-like structure. Fruits mature from early summer in the South to October in the North. Schwalbea is a hemiparasite (partially dependent upon another plant as host). Like most of the hemiparasitic Scrophulariaceae, it is not host-specific, so its rarity is not due to its preference for a specialized host.

Habitat

The American chaffseed inhabits open pine flat-woods, savannahs, and other open areas, in moist to dry acidic sandy loams or sandy pest loams in Florida, Georgia, Mississippi, New Jersey, North Carolina, and South Carolina. This species is associated with areas described as open, moist pine flat-woods, fire-maintained savannahs, ecotonal areas between peaty wetlands and xeric sandy soils, and other open grass-sedge systems. However, one population is known to occur in a heavy clay soil in a hayfield. This plant relies on fire, mowing, or fluctuating water tables to maintain the crucial open to partly-open conditions that it requires.

Historically, the species existed on savannahs and pinelands throughout the coastal plain and on sandstone knobs and plains inland where frequent, naturally occurring fires maintained these sub-climax communities. Under these conditions, herbaceous plants such as Schwalbea were favored over trees and shrubs.

Most of the surviving populations, and all of the most vigorous populations, are in areas that are still subject to frequent fire. These fire-maintained habitats include plantations where prescribed fire is part of a management regime for quail and other game species, army base impact zones that burn regularly because of artillery shelling, forest management areas that are burned to maintain habitat for wildlife including the endangered red-cockaded woodpecker, and various other private lands that are burned to maintain open fields. Fire may be important to the species in ways that are not yet understood, such as for germination of seed, or in the formation of the connection to the host plant.

Distribution

Historically, American chaffseed occurred in 15 states, including Alabama, Connecticut, Delaware, Florida, Georgia, Kentucky, Maryland, Massachusetts, Mississippi, New Jersey, New York, North Carolina, South Carolina, Tennessee, and Virginia at a total of approximately 78 sites. One historic record from Louisiana is now considered to have been erroneous. Currently, 51 populations are known, including one in New Jersey, one in North Carolina, 43 in South Carolina, four in Georgia, and two in Florida. American chaffseed was never considered to be common, but populations have declined and the range has seriously contracted in recent decades. The species can no longer be found in 10 of the states in which it occurred historically. Many historic populations have been confirmed extirpated due to habitat destruction, primarily due to development. Others have been lost in the absence of habitat destruction, probably as a result of fire exclusion.

Threats

American chaffseed has been eliminated from two-thirds of the states where it was historically reported to occur. The most serious threats to its continued existence are fire-suppression, conversion of the habitat for commercial and residential purposes, and incompatible agriculture and forestry practices. The loss of periodic fire from the landscape seems to be the most serious factor in its decline. Residential and commercial development adjacent to populations can also pose a threat since urbanization generally results in fire suppression. Fire suppression also favors the encroachment and invasion of exotic vegetation.

Sixty percent of known populations have been extirpated due to conversion of habitat to residential and commercial purposes, adverse agricultural and forestry practices, and encroachment of exotic vegetation. The sandy pineland where this plant is associated has been very vulnerable to development because the soils are level, deep, and suitable for building sites. Populations near the Atlantic Coast are particularly vulnerable to development pressures. In Florida, four of seven historic sites are confirmed extirpated as a direct result of habitat destruction. A New Jersey population was extirpated in 1968 by the construction of a residential street.

Conservation and Recovery

Most of the remaining populations are in South Carolina, on privately-owned plantations that are managed for quail and other game species. It is believed that the regular prescribed burning used to manage these lands has also provided and maintained the preferred habitat for this endangered plant. Populations located on federal lands, including Fort Bragg military reservation in North Carolina and the Francis Marion National Forest in South Carolina, are being protected and managed for the benefit of the species. The U.S. Forest Service in South Carolina, in cooperation with The Citadel, is conducting prescribed burning and transplantation experiments. Additional research into the species' life history and management requirements is underway at Ichauway Plantation (the Joseph Jones Ecological Research Center) in Georgia. Preliminary genetic analyses are underway at the University of Georgia.

Contacts

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

U.S. Fish and Wildlife Service
Regional Office of Endangered Species
300 Westgate Center Dr.
Hadley, Massachusetts 01035
http://northeast.fws.gov/

Asheville Ecological Services Field Office
U.S. Fish and Wildlife Service
160 Zillicoa St.
Asheville, North Carolina 28801-1082
Telephone: (828) 258-3939
Fax: (828) 258-5330

References

Porcher, R. D. 1994. "Transplant Study of Pondberry (Lindera melissifolia ) and Monitoring Study of American Chaffseed (Schwalbea americana )." Report submitted to U.S. Fish and Wildlife Service, Asheville, North Carolina, and South Carolina Heritage Trust Program, Columbia, South Carolina.

U.S. Fish and Wildlife Service. 29 September 1992. "Endangered and Threatened Wildlife and Plants; Endangered Status for Schwalbea americana (American Chaffseed)." Federal Register 57(189): 44703-44708.