Raleigh Ecological Services Field Office
Conserving the Nature of America

American chaffseed (Schwalbea americana)

American chaffseed. Credit: Elizabeth Evans

American chaffseed. Credit: Elizabeth Evans

Family: Figwort (Scrophulariaceae)

Federal Status: Endangered, listed September 29, 1992

Best Search Time: May through August (1 to 2 months after a burn)

Description: American chaffseed is an erect perennial herb with unbranched stems (or stems branched only at the base) with large, purplish-yellow, tubular flowers that are borne singly on short stalks in the axils of the uppermost, reduced leaves (bracts). The leaves are alternate, lance-shaped to elliptic, stalkless, 1 to 2 inches (2 to 5 centimeters) long, and entire. The plant is densely, but minutely hairy throughout, including the flowers. 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 that provides the basis for the common name. Fruits mature from early summer in the South to October in the North. American chaffseed 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: American chaffseed occurs in sandy (sandy peat, sandy loam), acidic, seasonally moist to dry soils. It is generally found in habitats described as open, moist pine flatwoods, fire-maintained savannas, ecotonal areas between peaty wetlands and xeric sandy soils, and other open grass-sedge systems. Chaffseed is dependent on factors such as fire, mowing, or fluctuating water tables to maintain the crucial open to partly-open conditions that it requires. Historically, the species probably existed on savannas 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.

map of Schwalbea americana distribution in North Carolina

Map of American chaffseed distribution in North Carolina.

Distribution: Currently, American chaffseed occurs in New Jersey, North Carolina, South Carolina, Georgia, and Florida. American chaffseed was never considered to be common, but populations have declined and the range has seriously contracted in recent decades.

Threats: Many historic populations have been confirmed extirpated due to habitat destruction, primarily due to development. Others have been lost in the absence of habitat management, most likely the result of fire exclusion.

References:

Buchanan, M.F. and J.T. Finnegan. 2010. Natural Heritage Program List of the Rare Plant Species of North Carolina. NC Natural Heritage Program, Raleigh, NC.

U.S. Fish and Wildlife Service. 1995. American Chaffseed (Schwalbea americana) Recovery Plan. Hadley, Massachusetts. 62 pp.

For More Information on American chaffseed...

Species Contact:

Dale Suiter, Fish and Wildlife Biologist, 919-856-4520 ext. 18

Species profile revised on July 26, 2011.

Last Updated: November 1, 2012