|Listed||November 3, 1998|
|Description||Perennial; bears yellow-petaled flowers.|
|Habitat||Shores of shallow, seasonally flooded ponds.|
Helenium virginicum (Virginia sneezeweed) is a perennial plant and a member of the aster family (Compositae or Asteraceae) known only from Augusta and Rockingham Counties, Virginia. The common name, sneezeweed, is based on the use of the dried leaves of these plants in making snuff, inhaled to cause sneezing that would supposedly rid the body of evil spirits. Virginia sneezeweed stems grow to a height of 1.5-3.5 ft (0.4-1 m) above a rosette of basal leaves. Coarse hairs are visible on the basal and lower stem leaves. The basal leaves may be broad in the middle tapering toward the ends, but otherwise may appear oblong. Stem leaves are lance-shaped, and become progressively smaller from the base to the tip of the stem. The stems are winged, the wings being continuous with the base of the stem leaves. The flower ray petals are yellow, and wedge-shaped with three lobes at the ends. The central disk of the flower is nearly ball-shaped. Flowering occurs from July to October.
H. virginicum is similar to common sneezeweed (H. autumnale ), but differs in having a sparsely leaved stem, larger basal leaves, and longer pappus scales (appendages that crown the ovary or fruit). It is also differentiated by leaf shape, stem and leaf hairs, and habitat requirements. Comparison of morphological and ecological characters with plants in common gardens and transplant sites clearly demonstrated that H. virginicum and H. autumnale were two distinct species.
Virginia sneezeweed disperses seeds in late fall and winter; the seeds germinate in late summer or early fall of the following year if conditions are suitable. Seeds will not germinate in the dark or under a standing column of water. In the first year of growth, the plant exists as a basal rosette with a diffuse root system. Plants seem to grow year-round, even while submerged. Flowering usually does not occur until the plant is more than one year old. Virginia sneezeweed forms one aerial stem bearing several flower heads during the first flowering season; in subsequent years it may form several flowering stems in a season. Plants may live for five years, flowering in consecutive years.
The species is a wetland plant found on the shores of shallow, seasonally flooded ponds in Virginia's Shenandoah Valley. The ponds supporting Virginia sneezeweed range in size from less than 0.1-8 acres (0.04-3 hectares) and are seasonally flooded or semipermanent bodies of water. These ponds have poorly drained, acidic, silty loam soils, and are typically flooded from January through July.
This rare plant is restricted to seasonally inundated sinkhole ponds and meadows in Augusta and Rockingham Counties, Virginia. Five of the 25 known extant populations are on U.S. Forest Service land; the others are on private land. From 1985-1995, extensive status survey work was conducted for Virginia sneezeweed in over 100 limestone sinkhole ponds along the western edge of the Blue Ridge Mountains in the Shenandoah Valley of Virginia. A total of 28 separate populations were located during these surveys.
In addition, one Helenium population with similarities to H. virginicum has been found near Pomona, Missouri. This population was originally described as a hybrid between H. autumnale and H. flexuosum. However, a 1995 study shows that this population of Helenium shares 12 of 15 morphological characters with H. virginicum, but indicates that more genetic and evolutionary study is necessary to clarify the relationship of this population with H. virginicum. Should further studies demonstrate that this population is H. virginicum, the existence of this single additional population would not significantly change the status of the species or the need to list it. Because this region of Missouri has been extensively surveyed over many years, it is unlikely that any additional H. virginicum -like populations occur there.
Virginia sneezeweed is adapted to survive the water level fluctuations of the seasonal ponds, giving it a competitive advantage in this habitat. From year to year, the number of Virginia sneezeweed plants at any given site may vary greatly. A high water level one year may leave the ponds flooded, resulting in less shoreline for plants to become established or to survive. However, a high water level also eliminates the invading shrubs and trees that may compete with Virginia sneezeweed on the pond shores. When the water level is lower, more pond shore is exposed and the surviving plants and the seeds stored in the soil enable the Virginia sneezeweed populations to rebound.
Of the 28 populations of Virginia sneezeweed identified during the 10-year survey period, 25 are currently extant. The remaining three populations, where no Virginia sneezeweed have been seen in recent years, may be extirpated. Of the 25 extant populations, five are on U.S. Forest Service land and the remaining 20 are on private lands. The most recent status report provides an excellent review of the status and trends for the species. The report indicates that the majority of sites on private land are in wetlands and continue to have a range of disturbances and threats including ditching, filling, mowing, and grazing.
Habitat modification is the principal threat to Virginia sneezeweed. The species is threatened by residential development, incompatible agricultural practices, filling and ditching of wetland habitats, groundwater withdrawal, and other disruptions of hydrology. Because the survival and maintenance of Virginia sneezeweed populations depend on seasonal water level fluctuations, either wetland drainage or increases in the time of inundation may cause high levels of mortality. Of the 18 populations visited in 1995, eight were located in relatively undisturbed wetlands, while the remaining 10 were in wetlands altered by ditching, mowing, grazing or filling. At least four of the sites where the species has dramatically declined in recent years have modified hydrology. Three of these sites have been either ditched or filled, thereby shortening or eliminating the wet phase.
Among the most threatened populations of Virginia sneezeweed are those in the area south and southwest of Lyndhurst, Virginia, where land use is increasingly being converted from agricultural to residential. Increased drainage control which accompanies such development will adversely affect many of the sites located on or near agricultural lands. The widening of Route 340 in Augusta County from two to four lanes, could have severe impacts on one of the largest populations of Virginia sneezeweed. However, it may be possible to avoid or reduce impacts by careful routing of the highway, controlling runoff, and maintaining current hydrology.
Cattle grazing and mowing affect many of the sites supporting the species. In general, moderate levels of grazing and mowing appear to be beneficial, since populations at several regularly grazed or mowed sites are among the largest and best established. Nonetheless, there is a potential that frequent, or poorly timed mowing (and perhaps over-grazing) could have a long-term adverse effect on the species by interfering with flowering and seed production.
Invasion of an exotic species, purple loosestrife, is a potential threat to Virginia sneezeweed. Purple loosestrife is slowly extending its range throughout freshwater wetland areas in Virginia and may invade Virginia sneezeweed habitats. Climate changes (either natural or human-caused) are also a potential threat to the species. Several consecutive years of unusually wet or unusually dry weather can dramatically lower population numbers. Based on a long-term demographic study of one Virginia sneezeweed site, it appears that Virginia sneezeweed is naturally at high risk of local extinction as a result of such events. Virginia sneezeweed is not self-fertilizing, and small populations are at risk of extirpation due to limited availability of compatible mates.
Conservation and Recovery
The State of Virginia currently lists Virginia sneezeweed as an endangered species. State law prohibits the taking of this species from state or private lands without consent of the landowner but does not protect the species' habitat. The Clean Water Act provides some regulation of the species' wetland habitats. These regulations have not prevented draining and filling of sites supporting the species. Therefore, existing regulations appear to be inadequate to protect the species.
Five of the species' 25 known extant populations occur on federal land in the George Washington and Jefferson National Forest. The Forest Service is aware of the locations of these populations and has protected four of them through designation of the sites as Special Interest Areas (Biological). The Forest Service likely will protect the fifth population, discovered more recently, by designating the site as a Special Interest Area also. The Forest Service has indicated a commitment to assisting in the recovery of this species by protecting these sites. In the unlikely event that the Forest Service would plan an activity that could potentially affect a population, it is highly likely that if the activity would cause adverse modification of critical habitat, it would also cause jeopardy to the species.
U. S. Fish and Wildlife Service
Chesapeake Bay Ecological Services Field Office
177 Admiral Drive
Annapolis, Maryland 21401-7307
Telephone: (410) 573-4500
Fax: (410) 263-2608
Blake, S. F. 1936. "A New Helenium from Virginia." Claytonia 3(2): 13-15.
Knox, J.S. 1997. "A Nine Year Demographic Study of Helenium virginicum (Asteraceae), a Narrow Endemic Seasonal Wetland Plant." J. Torrey Botanical Society 124(3): 236-245.
Knox, J. S., M. J. Gutowski, D. C. Marshall, and O.G. Rand. 1995. "Tests of the Genetic Bases of Character Differences between Helenium virginicumand H. autumnale Using Common Gardens and Transplant Studies." Syst. Bot. 20: 120-131.
Messmore, N. A., and J. S. Knox. 1997. "The Breeding System of the Narrow Endemic, Helenium virginicum (Asteraceae)." J. Torrey Botanical Society 124(4): 318-321.
Niering, W. A. 1979. The Audubon Society Field Guide to North American Wildflowers—Eastern Region. Alfred A. Knopf, New York.
Steyermark, J. A. 1960. "An Unusual Hybrid Helenium." Rhodora 62: 343-346.
U. S. Fish and Wildlife Service. 3 November 1998. "Determination of Threatened Status for Virginia Sneezeweed (Helenium virginicum ), a Plant from the Shenandoah Valley of Virginia." Federal Register 63 (212): 59239-59244.
Van Alstine, N.E. 1996. "A Reassessment of the Status of the Helenium virginicum Populations in the Shenandoah Valley of Virginia." Natural Heritage Technical Report 96-6. VA Dept. of Conservation and Recreation, Richmond, VA. Unpublished report to the U.S. Fish and Wildlife Service.
Van Alstine, N.E., and J.C. Ludwig. 1991. "Natural Heritage Inventory: Helenium virginicum. 1990 Final Report." Virginia Deptartment of Conservation and Recreation, Div. of Natural Heritage, Richmond, VA. Unpublished report.