American chaffseed, Schwalbea americana L., is a federally endangered hemiparasitic (a plant that obtains some nourishment from its host but also undergoes photosynthesis) herb that requires frequent fire or understory removal to persist across the landscape. Due to the disappearance of the species from over half of its range, American chaffseed was listed as an endangered species in 1992.
Historically this species occurred along the coast from Massachusetts to Louisiana and inland to Kentucky and Tennessee. Currently, this species occurs in seven states along the coast: New Jersey, North Carolina, South Carolina, Georgia, Alabama, Florida, and Louisiana. American chaffseed has continued to decline since it was listed due to the persistent threat of fire suppression which results in the species being outcompeted by other vegetation.
A range-wide Reintroduction Plan for American chaffseed is being drafted for this species to help guide future reintroduction efforts.
American chaffseed was selected as an indicator species for the South Atlantic Landscape Conservation Cooperative (SALCC) and a species distribution model will be developed in order to help guide conservation efforts across the southeast.
American chaffseed is an erect perennial herb with stems that branch only at the base. The leaves are alternate, have no outgrowths at their base, and are fixed and ascend in an overlapping spiral. The leaves, stems, and flowers are hairy throughout (villous-puberulent). The five-lobed flowers are reddish-purple and mature into capsules that burst open, containing numerous linear, yellowish-tan seeds. The showy flowers have a high degree of bilateral symmetry, elaborated for pollination by bees. Flowering occurs from April to June in the southern part of the species’ range, and from June to mid-July in the northern part of its range. Fruits start to mature in early summer in the South and October in the North.
American chaffseed is a hemiparasitic herb that parasitizes the root of a host plant by a specialized organ called the haustorium. Through the haustorium, it acquires nutrients and water from the host plant. Because American chaffseed retains chlorophyll and can undergo photosynthesis, it is a hemiparasite - only half parasitic. Although American chaffseed can form haustorial connections with a wide variety of species, narrowleaf silkgrass (Pityopsis graminifolia) appears to be a favorable host species along with other composites and grasses. This relationship may be due to the fact that composites and grasses have a higher density of roots near the soil surface, thereby increasing the likelihood that American chaffseed seedlings come into contact with the roots of host species. American chaffseed is considered the rarest root parasitic plant in the South. However, because there are many common hemiparasitic species, American chaffseed’s hemiparasitic nature does not necessarily contribute to its rarity.
Germination and seedling recruitment
In controlled conditions, germination is high (90%) for seeds sown immediately after collection (within 24 hours) and 1-2 years post collection. Due to American chaffseed’s hemiparasitic nature, seedlings have to be given additional nutrients or grown with host species such as narrowleaf silkgrass to survive off-site safeguarding efforts. Low soil moisture or low water availability may inhibit seed germination and seedling establishment. Because American chaffseed does not reproduce asexually and seeds do not appear to form a persistent seed bank, soil disturbance via prescribed fire or other disturbances that expose bare soil are critical to the recruitment and survival of this species. In the field, seedling recruitment appears dependent upon soil disturbances such as earthworm castings, pocket gopher activity, old fire plow lines and other minor disturbances that expose bare soil (i.e., prescribed fire). American chaffseed does not reproduce asexually via rhizomes, bulbs, etc.; thus recruitment is solely dependent upon sexual reproduction.
It has been demonstrated that buried American chaffseed seed will persist in the soil and remain viable for at least one year, but that no germination occurred for seeds stored in field conditions for five years, appearing incapable of long-term dormancy within the soil. Seeds retain viability after at least eight years of storage in refrigeration. More studies are needed across the species range to determine how long seeds remain viable in the seed bank on average.
The morphology of American chaffseed seed, somewhat flattened and compressed and enclosed in a loose-fitting sac-like structure, suggests wind dispersal; however, no information is available to support this hypothesis. Information is lacking on both the mechanism and distance of seed dispersal. Initial observations in New Jersey determined ants ignored American chaffseed seeds; therefore, ants are unlikely to serve as dispersal agents.
Life history traits correlated with a fire-prone ecosystem
After a fire, American chaffseed individuals will resprout and undergo rapid stem growth. Undeveloped buds have been found at the base of stems close to the soil surface and may play a role in the rapid stem elongation after a fire. Fire also stimulates flower production. The duration of the flowering response in American chaffseed is only one year based on an almost complete absence of flowering in years without prescribed fire. American chaffseed will change from a reproductive to a vegetative stage in order to persist between fire events. However, the length of time a population can persist in the absence of fire remains unknown. Population monitoring reports in South Carolina appear to suggest a trend of sharp population decline and/or extirpation following five years of fire suppression or exclusion for small populations. American chaffseed has a tolerated fire frequency range of 1-6 years and a pre-settlement fire frequency range of 1-3 years.
American chaffseed occurs in fire-maintained longleaf pine flatwoods and savannas. Often it is found in transition zones between peaty wetlands and xeric (dry) sandy soils. American chaffseed habitat has been described as open grass-sedge systems in moist acidic sandy loams or sandy peat loams. Chaffseed is dependent on factors such as fire, mowing, or fluctuating water tables to maintain the 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 American chaffseed 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 (such as the 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.
States with historic records only are Massachusetts, Connecticut, New York, Delaware, Maryland, Virginia, Mississippi, Louisiana, Texas, Tennessee, and Kentucky.
Currently, American chaffseed occurs in New Jersey, North Carolina, South Carolina, Georgia, Florida, Alabama, and Louisiana. American chaffseed was never considered to be common, but populations have declined and the range has seriously contracted in recent decades.
Fire suppression and competition from other plant species across the Atlantic and Gulf Coast regions remain the greatest threats to American chaffseed. Across this species range, the largest, healthiest populations are ones that are burned annually by quail plantation managers. Fort Bragg supports the largest populations on federal land due to 2-year fire return intervals from the military trainings. The high fire-return interval (1-3 years) needed to support viable populations can be difficult to maintain long-term due to fluctuations in funding and personnel. Other threats include habitat destruction due to development and an increase in the urban-wildlife interface that results in fire suppression. However, since effective management techniques (i.e. fire prescription) are known and the species occurs in a wide-ranging habitat (longleaf pine savannas and flatwoods), restoration can be achieved with the right management regime, giving American chaffseed a high recovery potential.
American chaffseed was listed as an endangered species under the Endangered Species Act in 1992. Download the recovery plan.
Actions Needed for Recovery
- Protect existing populations and manage habitat with a high fire return interval (1-3 years).
- Reintroduce American chaffseed into the northern and southern portion of the current range.
- Conduct research to determine species life history traits such as germination ecology.
- Determine if mowing can effectively serve as a surrogate for fire in populations that cannot be adequately managed with fire.
- Seek opportunities to include American chaffseed protection into Safe Harbor Agreements or Habitat Conservation Plans developed for red cockaded-woodpecker where the species co-exist.
Partnerships, Research and Projects
The Service works with federal, state, academic and non-profit organizations and private landowners across the southeastern United States to conserve American chaffseed.
The U.S. Forest Service maintains a prescribed fire program and tries to burn American chaffseed populations on a 2-3 year rotation. They have monitored American chaffseed populations on the Francis Marion National Forest since 1999.
Jeff Glitzenstein (Research Associate with Tall Timbers) worked with The Citadel (Danny Gustafson), S.C. Department of Natural Resources, and the U.S. Fish and Wildlife Service to introduce a population of American chaffseed onto Woods Bay Heritage Preserve.
Brandi Cannon, Masters Student with Columbia University, is researching the genetic variation of American chaffseed throughout its range. Listen to the In Defense of Plants podcast episode, Broomrapes: A celebration of an interesting family of parasitic plants.
The South Carolina Department of Natural Resources (SCDNR) has worked hard to restore the Lynchburg Savanna Heritage Preserve using prescribed fire as their management tool to help recover American chaffseed. Johnny Stowe, Heritage Preserve Land Manager, left a small portion (left side of photo above) of the preserve unburned to demonstrate the important role fire plays in creating and maintaining Longleaf Pine Savannas. Pictured above (l-r): Aaron Robinson, intern, South Carolina Department of Natural Resources and Johnny Stowe, Heritage Preserve Manager, South Carolina Department of Natural Resources.
Due to the decline of American chaffseed across its range, the Alabama Plant Conservation Alliance and South Carolina Plant Conservation Alliance have identified American chaffseed as a priority species for conservation.
How You Can Help
Education and Outreach
Education and outreach are powerful recovery tools and could lead to the discovery of new American chaffseed populations. Agencies and private landowners that manage longleaf pine forests on a frequent fire-return interval (1-3 years) should be aware of the potential for American chaffseed.
Hunt for American chaffseed
The Service needs more eyes and boots on the ground looking for American chaffseed! Surveys in some areas where American chaffseed had never been documented before have revealed additional populations. Several American chaffseed populations were found in powerline rights-of-ways in the 1990s in South Carolina. The likelihood still exists for undocumented American chaffseed populations persisting in powerline rights-of-ways, along roadsides, or within longleaf pine habitat that is being actively managed with fire within the species historic and current range.
Burn, Burn, Burn
For existing populations, the most important thing one could do to help recover American chaffseed is to burn on annual rotation or 1-3 year fire-return interval.
Subject Matter Experts
- April Punsalan, Botanist, 843-727-4707 ext. 218, email@example.com
- Dale Suiter, Fish and Wildlife Biologist, 919-856-4520 ext. 18, firstname.lastname@example.org
Designated Critical Habitat
There is no designated critical habitat for the species.
Other Scientific Resources
- U.S. Fish and Wildlife Service Environmental Conservation Online System Species Profile
- U.S. Department of Agriculture Natural Resource Conservation Service Plants Database
- Restoration work for the red-cockaded woodpecker (RCW) in southeast Alabama benefits American chaffseed.
- Jay Kelly gives a presentation on New Jersey ex situ efforts to the Philadelphia Botanical Club.
- Species Biology and Life History of the Federally Endangered Schwalbea Americana L. (Scrophulariaceae) by Amy Heather Norden, B.S., Florida State University, 1998
Federal Register Documents
The following Federal Register documents were automatically gathered by searching the Federal Register Official API with this species’ scientific name ordered by relevance. You can conduct your own search on the Federal Register website.
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