American Chaffseed - Schwalbea americana
By Van Whitehead, Former SCWF Staff
South Carolina is fortunate to host a high percentage of the beautiful American Chaffseed (Schwalbea americana), which was designated as a federally endangered species in 1992. A recent tally reported 51 populations in the United States: 43 in South Carolina, 4 in Georgia, 2 in Florida, 1 in New Jersey, and 1 in North Carolina.
Although never that common, this plant historically was found throughout much of the eastern United States, but it is now limited to a range stretching from Louisiana to North Carolina, and a pocket in New Jersey. The major threats leading to the loss of this species from two-thirds of the states where it was historically found are outright habitat destruction from land conversion and changes in natural disturbance cycles, such as forest fires and flooding. Without these disturbances, American Chaffseed is overrun by larger and more aggressive plant species.
American chaffseed, which is only 1-2 feet tall, is a perennial herb that branches only at its base and displays large, purplish-yellow, tubular flowers on its top. Its alternate, elliptical leaves are about an inch long and attach closely to the stem. Aside from being a relatively leafy plant, small dense hairs cover the entire plant – even the flowers. Just remember that the best identifying features are the flowers, which bloom from April to June. The resulting fruits are long, narrow capsules and they mature from summer into the fall, depending on the location.
Perhaps one of the most interesting things about American Chaffseed is that it is a hemiparasite, which means it is partially dependent upon another plant as a host. Specifically, it draws nutrients from the roots of other plants through a special structure called a haustoria. It isn’t too selective about its hosts and is found to use roots of various trees, such as sweet-gum, bald cypress, hackberry, and various oaks and pines.
American chaffseed occurs in sandy acidic, seasonally moist to dry soils that are common in the coastal plain. It is generally found in habitats described as open, moist pine flatwoods, fire-maintained savannas, transition areas between peaty wetlands and dry sandy soils, and other open grass-sedge areas. Because it is not tolerant of dark shades, the American chaffseed is usually found along the margins of forest or woodlands.
Many of the surviving populations are located in areas where the landscape is managed with prescribed fires, whether for timber, wildlife or otherwise. It is possible that fire also is important in the germination of the Schwabia seeds or forming connections with a host plant. Also, insect pollinators play a critical role in maintaining a healthy population. Clemson University’s agricultural cooperative discourages the aerial application of the pesticide “Pirate” within one mile of native vegetation in the counties likely to host Schwalbia.