Description
An erect perennial with unbranched stems or branched only at base, growing to 3-6 dm (to 8 dm, Musselman and Mann 1978), with solitary, two-lipped, yellow and purplish or reddish flowers. Leaves are largest at the base of the plant and gradually diminish in size towards the top of the stem. The 2-lipped flowers are yellow, suffused with purple. This species is parasitic on the roots of a wide variety of woody and herbaceous plants.
This species produces showy, insect-pollinated flowers; the high degree of zygomorphy elaborated for pollination by bees (Pennell 1935).
Habitat
This species occurs in seasonally wet acidic, sandy or peaty soils in open pine flatwoods, pitch pine lowland forests, seepage bogs, palustrine pine savannahs, and other grass- and sedge-dominated plant communities, and often subject to fires in the growing season. Frequently grows in ecotonal areas between peaty wetlands and xeric sandy soils. In these situations, individuals sometimes extend well into the drier communities, but seldom into the areas that support species characteristic of wetter soils. Surrounding plant communities are typically species-rich (Porcher 1993, Rawinski and Cassin 1986).
Schwalbea americana is primarily a Coastal Plain species of the Atlantic and Gulf coasts, with historic locations ranging from Massachusetts to Florida to east Texas. Exceptions include: a historic occurrence in sandplains near Albany, New York, which Pennell (1935) considered a remnant population of possible glacial migration along the shores of the Hudson River; a westernmost occurrence in Tennessee and Kentucky, these from sandstone knobs and ridges of the Cumberland Plateau and Highland Rim; and an inland site on the Montague Sandplain near the Connecticut River and a sandplain in Hubbardston in Massachusetts.
In South Carolina, plants are found in flatwoods, which are generally dominated by Pinus palustris with Quercus stellata and Quercus marilandica as associates. Some sites support only oaks now, although it is believed that longleaf pine was once a component. Tephrosia virginiana and Pterocaulon pycnostachyum are present in almost every site, which are sandy, moist to dry, grassy areas. The fire regime at these sites, either prescribed or natural (or a combination of both), is a mixture of growing-season and non-growing-season burns; it is unknown what mix best favors chaffseed. Growing-season burns maintain the grassy areas chaffseed depends upon for survival (Porcher 1993).
In North Carolina, the species occurs on moist to dryish pine flatwoods, pine savannas, and on longleaf pine/oak sandhills, composed of Upper Cretaceous deep, white sands, at the western edge of the Coastal Plain. The vast majority of plants in North Carolina's Sandhills occur in sites much drier than anticipated from the conventional concepts derived from floras, literature reports, etc. (TNC and NCNHP 1993). Since so few field botanists have encountered the species during the past 50 years, there is little wonder that, at least in North and South Carolina, misconceptions have arisen over chaffseed's preferred habitat. Of all the pocosin ecotone species on Fort Bragg, Schwalbea americana is among the least moisture-dependent; soil descriptors such as "peaty" and "seasonally wet" are quite misleading. It is also often found growing in close proximity to a number of other rare Sandhills species such as Onosmodium virginianum, Phaseolus sinuatus, Pteroglossaspis ecristata, Solidago verna, Tofieldia glabra (to a lesser degree), and Tridens carolinianus (TNC and NCNHP 1993). In Virginia, a historic occurrence of Schwalbea americana along the fall belt was in moist to dry woods and clearings. Fernald (1939) reports Buchnera americana (=B. floridana) as an abundant associate.
Associated genera reported to occur in the Southeast include grass species of Andropogon, Aristida, Panicum, and Paspalum; sedge species of Carex, Dichromena, Fimbristylis, Rhynchospora, Scleria, and other monocot species of Aletris, Calopogon, Eriocaulon, Juncus, Lachnocaulon, Xyris; as well as dicot species of Asclepias, Erigeron, Eryngium, Helenium, Heterotheca, Orbexilum, Phlox, and Polygala. In wetter sites ("grass-sedge complexes interrupted by stands of shrubs"), species of Cliftonia, Gaylussacia, Ilex (glabra, coriacea), Lyonia, Leucothoe, Myrica, and Vaccinium occur as associates (Kral 1983c).