Helenium virginicum - Blake
Virginia Sneezeweed
Other Common Names: Virginia sneezeweed
Taxonomic Status: Accepted
Related ITIS Name(s): Helenium virginicum S.F. Blake (TSN 502914)
Unique Identifier: ELEMENT_GLOBAL.2.134817
Element Code: PDAST4L0K0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Aster Family
Image 21708

© Alfred R. Schotz

Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Asterales Asteraceae Helenium
Check this box to expand all report sections:
Concept Reference
Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Helenium virginicum
Taxonomic Comments: Knox et al. (1995) determined that H. virginicum is distinct from H. autumnale morphologically and ecologically. Genetic work by Simurda and Knox (2000) supported treating H. virginicum and a Pomona, Missouri, Helenium sp. as a monophyletic group. Additional genetic work with a larger number of Helenium populations over a broader geographic range strengthened this conclusion and determined a narrow-leaved Helenium autumnale population from the Bruce Peninsula in Ontario, Canada, to be a sister group to the Virginicum group (Simurda et al. 2005).
Conservation Status

NatureServe Status

Global Status: G3
Global Status Last Reviewed: 05Oct2005
Global Status Last Changed: 05Oct2005
Rounded Global Status: G3 - Vulnerable
Reasons: A limited amount of habitat in two Virginia counties and six Missouri counties make up this species' entire global range. There are currently 61 documented occurrences, although 4 or fewer may not be extant, with the majority in Missouri as of 2006. The Virginia occurrences are restricted to small, discrete areas around sinkholes, and occupying, in total, less than 20 acres (8 ha). Missouri occurrences occupy ca. 11 acres within both discrete and less discrete wetland habitat. Six Virginia occurrences are currently protected by being on National Forest land or within state preserves. Only 9 Missouri occurrences have some protection although not complete. Sites in both states are threatened by drainage and residential development.

Nation: United States
National Status: N3

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Missouri (S3), Virginia (S2)

Other Statuses

U.S. Endangered Species Act (USESA): LT: Listed threatened (03Nov1998)
Comments on USESA: Formerly a candidate for federal listing as endangered from 1983-1997. It was proposed threatened by the USFWS on September 29, 1997. It was federally listed threatened on November 3, 1998.
U.S. Fish & Wildlife Service Lead Region: R5 - Northeast

NatureServe Global Conservation Status Factors

Range Extent Comments: About 4,150 km2.

Virginia: About 165 km2 . As this plant is found within fairly discrete wetlands in Virginia, the range extent includes large areas of unsuitable or unoccupied habitat. The area was estimated by drawing a boundary connecting the known occurrences and extent of likely habitat.

Missouri: About 3,983 km2 in polygon drawn around the native occurrences.

Area of Occupancy: 26-2,500 4-km2 grid cells
Area of Occupancy Comments: About 30 acres.

Virginia: Plants are limited to discrete habitats of <0.1 -6 acres (avg. ca. 1 acre although most of the wetland are far less than this). Area of occupancy estimated to be less than 20 acres.

Missouri: About 11 acres of occupancy.

Number of Occurrences: 21 - 300
Number of Occurrences Comments: About 60 known occurrences with additional populations expected with further survey.

Virginia: The number of Virginia documented occurrences has been revised downward to 17 by using a 1 km separation distance between occurrences (J. Townsend, VA Dept. of Conservation and Recreation, 2006 pers. comm.) These 17 occurrences had previously been recognized as 30 occurrences, with an occurrence at that time being equal to the plants within a discrete pond or wet meadow. It is expected that additional survey work will find more occurrences within the 21-80 range; some of these may be within the more disturbed farm pond type of habitat. As most of the sites in Virginia have not been visited since 1995, it is not known how many are currently extant. Based on what was known at the time the draft Recovery Plan was written in 2000 there were 4 sites where plants had not been seen over several years of surveys (U.S. Fish and Wildlife Service 2000). The Virginia occurrences were located during extensive survey work from 1985 to 1995 in over 100 limestone sinkhole ponds along the western edge of the Blue Ridge Mountains in the Shenandoah Valley of Virginia (FWS 1998).

Missouri: In 2000, a population of a Helenium sp. in a sinkhole pond near Pomona, Missouri , was determined to be H. virginicum, based on genetic work conducted by Simurda and Knox (2000). By early 2006, 44 native occurrences had been found within 6 counties: Howell (23), Oregon (1), Shannon (15), Texas (3), Webster (1), and Wright (1). All are within the Ozark Highlands in southern Missouri. The 1 km separation distance was used to define occurrences (Tim Smith, Missouri Dept.of Conservation, pers. comm. 2005). In addition, plants have been introduced at 9 sites, 3 on state lands and the remainder private. Probably 50% of the potential habitat remains to be surveyed.

Population Size Comments: In Virginia 2500-10,000; in Missouri over 10,000. In Virginia most of the sites have not been reassessed since 1995. Widely fluctuating population numbers have been taken into consideration: a population of 10, 000 one year may be reduced to a handful in years of drought or prolonged inundation.

Number of Occurrences with Good Viability/Integrity: Some (13-40)
Viability/Integrity Comments: More than 30 with good viability.
Virginia: 6 occurrences (based on revised occurrence number) with excellent/good viability.
Missouri: 28 occurrences with excellent/good viability.

Overall Threat Impact: Unknown
Overall Threat Impact Comments: In Virginia the long-term viability of existing populations is primarily threatened by human-induced disruptions of hydrologic regimes, particularly by encroaching agriculture, residential land development, and logging (Van Alstine 1991; J. Knox, C. Williams pers. obs.). In addition, a private site and adjacent sites on the George Washington National Forest are sporadically impacted by off road vehicles (e.g., during summer 1991 on the private land; J. Knox, C. Williams, pers. obs.).

Exotic organisms may pose threats to H. VIRGINICUM populations in the near future. Purple loosestrife, LYTHRUM SALICARIA, is slowly spreading through Virginia and may eventually invade some H. VIRGINICUM sites, especially following disturbances to hydrologic regime and/or substrate. The gypsy moth, LYMANTRIA DISPAR, is currently defoliating large areas of the George Washington National Forest and adjacent lands but it is unclear whether the gypsy moth will negatively impact H. VIRGINICUM populations. For example, as H. VIRGINICUM is shade-intolerant, defoliation of trees and shrubs that grow on the periphery of sinkholes may increase light availability and allow H. VIRGINICUM to expand into areas from which it was formerly excluded.

The following paragraphs are taken, with modifications, from U.S. Fish and Wildlife Service (2000):
The most serious threat to H. virginicum appears to be habitat loss, most often arising from changes in the natural hydrological regime of the sinkhole pond habitat. Four of the sites, three of which are grazed by cattle, have had a portion of the wetland deepened to create a permanent pond; prior to being excavated, much of this section once undoubtedly supported H. virginicum and so loss of some habitat has occurred. In contrast, actions have been taken at some of the Virginia sites to stop or lessen the periodic inundation. Significant ditches have been dug at two sites, with smaller ditching at three sites. Ditching and plowing occurred at one site in the past, and some evidence of the ditch remains, but does not significantly affect the hydrologic regime. Portions of the sites at 2 sites have been filled in. It is safe to assume that the pressure to control seasonal flooding will only increase, as the area of the Shenandoah Valley where the Virginia populations of H. virginicum are found is experiencing rapid growth, particularly in the building and expansion of residential subdivisions.

In addition to obvious hydrological alterations made directly to the sinkhole ponds, off-site actions may affect the hydrology of the ponds. Input from groundwater sources may be decreased by withdrawals for wells for adjacent developments such as subdivisions. Overland surface water flow may be altered by activities such as timber harvesting or road building in upslope areas. Little is known about the relative importance of groundwater vs. surface flow to the hydrological regime of the sinkhole ponds, but preliminary research suggests that the relative importance of these water sources is unique for each pond (E. Knapp, Washington and Lee University, pers. comm.).

A variety of site-specific threats to H. virginicum from habitat loss have appeared over the last ten years. The Virginia Department of Transportation (VDOT) has proposed to widen to four lanes Route 340, a currently two lane north-south corridor on the east side of the Shenandoah Valley. A portion of one site in Augusta County is immediately east of Route 340. The Virginia Department of Conservation and Recreation's Division of Natural Heritage reviewed the proposal for this project in 1991 and recommended against any road widening to the east in the area of the pond and further recommended that VDOT consult with the U.S. Fish and Wildlife Service before any construction began. While the long range plans still include widening Rt. 340 to 4 lanes in this section, this project is not active; VDOT will coordinate with USFWS whenever the project becomes active (S. Stannard, VDOT, pers. comm.)

Another H. virginicum population is near the site of silos built in the early 1990's that are used to store septic waste. This waste is eventually dumped on the ground elsewhere on this landowners' ridge-top property and not near the H. virginicum site. However, in a 1995 site visit by DCR-DNH a large pile of soil was present on the north side of the shallow basin that supports the H. virginicum population. The landowner was considering pushing the soil into the seasonally wet basin to level it out, but was agreeable to not do that. In a 1997 site visit the pile was still present and was larger than in 1995. In 1995 and 1997, it was noted that sediment from the pile had washed into the edge of the pond site, creating different soil conditions in that area and making it more favorable for weedy species (DCR-DNH database).

Mowing occurs in at least 3 of the Virginia sites. Continued mowing may provide beneficial effects to the species; a site that is one of the largest if not the largest and densest population, has been periodically mowed and bush-hogged by the landowner for an extended period of time. Repeated mowing before seed is set and the seed bank is replenished, may lead to local extinction as vegetative plants die out and the seed bank ultimately becomes depleted.

Herbivory does not appear to be a problem; however, the threat to H. virginicum from cattle grazing needs evaluation. Large populations of H. virginicum co-exist in three sites with cattle grazing. This suggests that the species may respond favorably to limited amounts of disturbance. Knox et al. (1999) tested the hypothesis that H. virginicum is unpalatable to generalist herbivores in a common garden study; none of the H. virginicum plants were grazed by either vertebrate or invertebrate herbivores. Knox notes that this is consistent with reports of toxicity in other Helenium species associated with the presence of sesquiterpene lactones (Hesker 1982, Anderson et al. 1983, Anderson et al. 1986, Arnason et al 1987). Helenium virginicum has been shown to contain a sesquiterpene lactone, virginolide (Herz and Santhanam 1967). According to J.S. Knox (pers. comm.), the leaves of H. virginicum are bitter-tasting; selective grazing by cattle of more palatable associated species therefore may eliminate plant competitors. However, other effects on H. virginicum from cattle grazing such as the increased nutrient loads, soil compaction, and trampling of plants are unknown. As the soils of the H. virginicum sites have been found to be nutrient-limiting (Knox 1997), long-term nutrient enrichment from cattle could ultimately create more favorable habitat for other plant species.

With federally listed wetland species, the federal permitting process carried out by the US Army Corps of Engineers (USACOE) under authority of the Clean Water Act of 1977, is often the point at which proposed actions can be reviewed in light of their effect on a federally listed species and protection actions can be recommended. The isolated and often small seasonally wet habitat of Helenium virginicum, however, does not currently have direct federal protection. United States vs. Wilson 133 F. 3d 251(4th Cir. 1997) ruled that the USACOE has no jurisdiction over isolated water bodies that have no surface connection with any tributary stream that flows into traditional navigable waters or interstate waters. Nationwide Permit 26, under federal wetlands regulations (56 CFR 59134-59147, Part 330-Nationwide Permit Program), which has applied to headwater areas and isolated wetlands, is currently being revised including a lower minimum acreage (1/10 acre); the Norfolk District of the USACOE is proposing a regional minimum threshold of 1/4 acre (E. Gilinsky, DEQ, pers. comm.). These lower minimum acreages, however, will not apply to the Helenium virginicum habitat if the ruling in U.S. vs. Wilson stands.

Currently, so-called Tulloch ditching, draining by ditching in which excavation occurs by mechanical means that do not require placing excavated material into a wetland and in which the material is lifted and hauled to an upland disposal site, does not require that USACOE be notified or a permit obtained. Major ditching has been used at three of the H. virginicum sites to control the seasonal flooding with more minor ditching used at another three sites.

As most of the populations of H. virginicum are on private lands, the current legal protections in place for this species will not be adequate to insure the long-term survival of H. virginicum. The effects of future regulation changes are not known.

Extremes in the fluctuating hydroperiod of the sinkhole ponds could, when preceded by low investment in the seed bank, result in the local extinction of populations. Extended drought at a site could make a site more favorable for colonization by other plants previously hampered by the periodic inundation of the site. This would include tree species, which could result in increased shading within the site and so reduce the areas favorable for H. virginicum. An extended period of inundation, coupled with development of a floating vegetation mat, such as occurred at one site (Knox 1997), could lead to local extinction if an insufficient seed bank existed to recover from the death of the vegetative plants. Either of these extremes in hydroperiod could result from normal variability in weather patterns or from larger scale climate changes, of either natural or human origin.

If found to hold true for other populations of H. virginicum, the self-incompatible breeding system of H. virginicum found in one of the populations may eventually lead to local extinction at sites with low population numbers as the chance of successful pollination decreases (Messmore and Knox 1997).

In Missouri threats include grazing and/or trampling of plants in the pasture sites and haying of the plants during the growing season. Herbicide or plant growth hormones used on roadside pose a threat to the roadside populations.

Short-term Trend: Unknown
Short-term Trend Comments: Virginia: Designation of a short term trend is made difficult by the widely fluctuating populations that characterize this species and the lack of monitoring data. Many of the sites have only been visited 1 to 3 times with no visits since 1995. There are a few sites where no plants have been found over two different years and it is suspected that these populations are no longer extant. Site visits to several sites found reduced populations after ditches were created within the sites to control the seasonal flooding, but follow up visits have not been made.

Missouri: No trend can be estimated as all but one of the populations have been discovered in the last couple of years.

Long-term Trend: Unknown
Long-term Trend Comments: Virginia: As this plant was only described in 1936, a long term trend cannot be discussed.
Missouri: Historical trend unknown as most populations were only found in 2003-2005.

Intrinsic Vulnerability Comments: Species exhibits high tolerance to mechanical disturbance.

Other NatureServe Conservation Status Information

Global Range: About 4,150 km2.

Virginia: About 165 km2 . As this plant is found within fairly discrete wetlands in Virginia, the range extent includes large areas of unsuitable or unoccupied habitat. The area was estimated by drawing a boundary connecting the known occurrences and extent of likely habitat.

Missouri: About 3,983 km2 in polygon drawn around the native occurrences.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States MO, VA

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
MO Boone (29019)*, Cape Girardeau (29031), Christian (29043), Dent (29065), Howell (29091), Oregon (29149), Shannon (29203), Texas (29215), Webster (29225), Wright (29229)
VA Augusta (51015), Rockbridge (51163), Rockingham (51165)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
02 South Fork Shenandoah (02070005)+, Maury (02080202)+
07 Upper Mississippi-Cape Girardeau (07140105)+
10 Upper Gasconade (10290201)+, Big Piney (10290202)+, Lower Missouri-Moreau (10300102)+*
11 James (11010002)+, Bull Shoals Lake (11010003)+, North Fork White (11010006)+, Current (11010008)+, Spring (11010010)+, Eleven Point (11010011)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
Basic Description: A perennial herb, 7-11 dm tall. Some Missouri plants reach 17 dm in height (Tim Smith, Missouri Dept. of Conservation, pers. comm. 2006). Basal leaves form a rosette and may be broad in the middle tapering toward the ends, but otherwise may appear oblong. Stem leaves are lanceolate and become progressively smaller from the base to the tip of the stem. Stems are winged, wings being continuous with the base of the stem leaves. Flower ray petals are yellow and wedge shaped with three lobes at the ends. Central disk is nearly ball-shaped. Clusters of golden-yellow flower heads bloom from July to September.

Technical Description: HELENIUM VIRGINICUM is an herbaceous, fibrous-rooted perennial in the Asteraceae. When mature, the plant ranges from ca. 4-11 dm. in height. The elongate basal leaves are elliptic to oblanceolate, and larger than the progressively reduced and relatively few, persistent, cauline leaves. Cauline leaves are lanceolate to oblong or lanceolate-linear, exceeding or about equaling the internodes, are entire or nearly so, and do not taper toward the base. The basal leaves, lower cauline leaves and lower stem are pilose. The stem is winged with decurrent leaf bases. Several flower heads are borne in an open, sparsely-leafed inflorescence. Flower heads are hemispheric or subglobose; the disk is yellow, about 11-16 mm. wide. The rays are pistillate, yellow, about 11-16 mm. long and trilobed. Pappus scales are white-hyaline, about 0.9 to 2 mm. long, ovate or oblong-ovate, rather abruptly narrowed to a slender awn-tip about as long as the body. Corollas abscise readily from the maturing achenes.
Ecology Comments: HELENIUM VIRGINICUM flowers from early July to October, with peak flowering occuring in late July to early August at most sites. The pollination biology of H. VIRGINICUM has not been studied in detail; however, cursory observations conducted at Kennedy Mountain Meadow suggest that the primary insect pollinators are bees, wasps (Hymenoptera: Apidae, Halictidae, Sphecidae), butterflies (Lepidoptera: Hesperiidae and Lycaenidae, among others), and hoverflies (Diptera: Syrphidae) (C. Williams, pers. obs.). During favorable years at Kennedy Mountain Meadow, approximately one quarter of the H. VIRGINICUM population may flower (Knox and Williams 1988). Flowering appears to correlate with water availability during late spring and early summer, a critical period for bolting and flower formation in H. VIRGINICUM (Knox et al. 1987).

Seasonal water fluctuation, particularly inundation, is probably a key factor affecting recruitment and maintenance of H. VIRGINICUM populations (J. Knox, unpubl.). For example, extensive periods of inundation during the growing season may greatly limit recruitment and result in high levels of mortality in established plants. Reestablishment of inundation-depleted populations may be facilitated by a soil seed bank; viable seeds of H. VIRGINICUM can persist in the soil for at least two years (J. Knox, pers. obs.). Thus H. VIRGINICUM appears to be a "boom-bust" species in which recruitment is keyed by water fluctuations: population peaks occur in years of abundant soil moisture and troughs in years of excessive and persistent inundation. In addition, seasonal water fluctuations may also modulate populations of co-occuring plants that compete with H. VIRGINICUM for space and resources.

Surprisingly, H. VIRGINICUM appears to benefit from grazing. The stems and leaves of this species are extremely bitter in taste and apparently unpalatable, thus selective grazing by cattle may eliminate competing plants (John Knox, pers. obs.). Moreover, the largest (100,000 - 1,000,000 plants) and densest H. VIRGINICUM population (> 400 plants/m2) grows at a site that is mowed yearly.

Habitat Comments: Virginia: Helenium virginicum is a wetland plant restricted to shallow, seasonally inundated ponds (which are in or near sinkholes) in Augusta and Rockingham Counties, Virginia (Blake 1936; Roe 1977; Harvill et al. 1986). The pond basins in which this species occurs are usually flooded from January to July. The substrate at most H. virginicum sites consists of poorly drained, acidic, low fertility Purdy silt loams (USDA 1979) underlain by gray clays and dolomitic bedrock (Werner 1966; Rader 1967).

The following description of the Virginia habitat is from U.S. Fish and Wildlife Service (2000):
Ponds supporting Virginia sneezeweed vary in size, basin depth and shape, and length of hydroperiod. While many of the wetlands appear pond-like, consisting of more or less circular water-filled depressions with concentric vegetation zones, others within shallow basins are more meadow-like in physiognomy with little well-defined vegetation zonation. The level of disturbance present at the sinkhole ponds includes relatively undisturbed ponds surrounded by forest, more meadow-like habitats around farm ponds actively used by cattle, a backyard seasonal wetland maintained in an open state by the landowner, a seasonally wet mowed lawn, and a seasonal wetland degraded by severe cattle trampling and an ongoing attempt to fill the site.

At Kennedy Mountain Meadow in Augusta County, the type locality, Helenium virginicum occurs with the following plants: Sphagnum sp., Eleocharis acicularis, E. melanocarpa, Scirpus cyperinus, Panicum agrostoides, P. verrucosum, Hypericum boreale, Boltonia [new species, currently (2006) being described] Erechtites hieracifolia, Viola lanceolata, Cephalanthus occidentalis, Acer rubrum, Nyssa sylvatica, Quercus palustris, and Diospyros virginiana (Knox et al. 1986).

Missouri: Found on sinkhole pond margins and wet meadows in the Ozark Highlands (Rimer and McCue 2005). The plant has been found to prefer open growing conditions and is found in a variety of sites in addition to the less disturbed sinkholes and wet meadows including rural airports, roadside ditches, and cattle ranches (R. Rimer and J. Summers, pers. comm. 2005). It appears to be less confined to discrete wetlands in Missouri and can occur in a temporarily wet portion of a hayfield or in roadside ditches (Tim Smith pers. comm.).

Economic Attributes Not yet assessed
Management Summary
Stewardship Overview: The key to stewardship of Helenium virginicum populations is the preservation of habitat and maintenance of natural hydrologic regimes. Preserve designs must ensure defensibility of the hydrologic regime in order to maintain viable populations of these plants. Monitor all populations and study disturbed sites to determine long-term viability of populations.
Restoration Potential: The recovery or restoration of Helenium virginicum populations at historic or degraded sites would depend heavily on the restoration of the natural hydrologic regime. Sites that have been filled, ditched, or the natural substrate removed or otherwise altered, have relatively poor potential for reintroduction of H. virginicum. However, sites on which H. virginicum was extirpated by natural processes may be prime for reintroduction if the hydrologic regime remains intact.
Management Requirements: No active management of HELENIUM VIRGINICUM populations is needed at this time.
Monitoring Requirements: Development of demographic monitoring programs for Helenium virginicum at a (particular) George Washington National Forest site is needed to provide an overall assessment of the population dynamics of this species. In addition, monitoring of populations subjected to periodic grazing or mowing would provide useful information on the demographic responses of H. virginicum to wounding and control of competitors.
Monitoring Programs: A long-term demographic study of the Helenium virginicum population at a National Forest site is being conducted by Dr. John Knox. Fifty-three randomly selected 1 m2 permanent plots were established at the 1.05 hectare site in 1986. Yearly, during the late flowering season, the coordinates of individual H. virginicum plants within each plot are mapped and the developmental stage and reproductive status recorded. Water depth is measured at the site monthly throughout the year and macrophyte cover is estimated in the fall by a point intercept method.
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
NatureServe Conservation Status Factors Edition Date: 01Feb2006
NatureServe Conservation Status Factors Author: N.E. Van Alstine and J. Townsend, VA Dept. of Conservation and Recreation (VANHP)/T. Smith/R. Rimer, Missouri Dept. of Conservation, 1/2006

Management Information Edition Date: 22Aug1991
Management Information Edition Author: JAN CASSIN (1987); JOHN S. KNOX, CHARLES E. WILLIAMS (UPDATE 1991)

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

  • Anderson, A.C., A.C. Jones, L.P. Wilson, R.D. Kim, and H.L. Bailey. 1983. Acute toxicity of smallhead sneezeweed in sheep. Sheep and Goat, Wool and Mohair -Texas Agricultural Experiment Station, Research Reports, pp. 118.

  • Anderson, A.C., L.P. Jones, and H.L. Kim. 1986. Acute helenalin toxicity in sheep. Sheep and Goat, Wool and Mohair-Texas Agricultural Experiment Station, Research Reports. pp.21.

  • Arnason, J.T., M.B. Isman, B.J.R. Philogene, and T.G. Waddell. 1987. Mode of action of thesesquiterpene lactone, tenulin from Helenium amarum against herbivorous insects. Journal of Natural Products 50: 690-695.

  • Blake, S.F. 1936. A New Helenium from Virginia. Claytonia 3:13-15.

  • Gleason, H.A., and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. New York Botanical Garden, Bronx, New York. 910 pp.

  • Harvill, A.M., Jr, T.R. Bradley, C.E. Stevens, T.F. Wieboldt, D.M.E. Ware, and D.W. Ogle. 1986. Atlas of the Virginia Flora, 2nd edition. Virginia Botanical Associates, Farmville, Virginia.

  • Herz, W. and P.S. Santhanam. 1967. Constituents of Helenium species. XX. Virginolide, a newguaianolide from Helenium virginicum Blake. Journal of Organic Chemistry 32:507-509.

  • Hesker, K. 1982. Orange sneezeweed: "beautiful flower of death" Helenium hoopesii, poisonous to sheep. Rangelands 4: 210-211.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Knox ,J.S., F.W. Stearns, Jr., and C.L Dietzel. 1999. Factors controlling the distribution and abundance of the narrow endemic, Helenium virginicum (Asteraceae): antiherbivore defense? Banisteria 13:95-100.

  • Knox, J.S. 1997. A nine year demographic study of Helenium virginicum (Asteraceae), a narrow endemic seasonal wetland plant. J. of the Torrey Botanical Society 124 (3): 236-245.

  • Knox, J.S. , M.J. Gutowski, , D.C. Marshall, and O. Gray Rand. 1995. Tests of the genetic bases of character differences between Helenium virginicum and H. autumnale (Asteraceae) using common gardens and transplant studies. Sytematic Botany 20 (2): 120-131.

  • Knox, J.S. 1987. An experimental garden test of characters used to distinguish Helenium virginicum Blake from H. autumnale L. Castanea 52:52-58.

  • Knox, J.S. and G. Williams. 1988. A progress report on ecological studies of the Kennedy Mountain Meadow population of Helenium virginicum. Unpublished report submitted to The Nature Conservancy, Virginia Field Office, Charlottesville, Virginia. 4 pp.

  • Knox, J.S., G. Caldwell, and R. Hawkins. 1986. Report on ecological studies of the Kennedy Mountain Meadow population of Helenium virginicum. Dept. Biology, Washington and Lee Univ., Lexington, VA.

  • Knox, J.S., H. Harden, J. McKay, and G. Schott. 1987. A progress report on ecological studies of the Kennedy Mountain Meadows population of Helenium virginicum - 1987. Dept. Biology, Washington and Lee Univ., Lexington, VA.

  • Messmore , N.A. and J.S. Knox 1997. The breeding system of the narrow endemic, Helenium virginicum (Asteraceae). J. of the Torrey Botanical Society 124 (4): 318-321.

  • Rader, E.K. 1967. Geology of the Staunton, Churchville, Greenville, and Stuart's Draft quadrangles, Virginia. Virginia Division of Mineral Resources. Report #12.

  • Rimer, R.L. and K.A. McCue. 2005. Restoration of Helenium virginicum Blake, a threatened plant of the Ozark Highlands. Natural Area Journal 25 (1): 86-90.

  • Rock, H.F.L. 1956. A revisional study of the decurrent-leaved species of the genus Helenium L. (Compositae). Ph.D. dissertation. Duke University, Durham, North Carolina.

  • Roe, G. F. 1977. Helenieae (Asteraceae) in Virginia. Castanea 42:42-50.

  • Simurda, M. C. and J. S. Knox. 2000. ITS sequence evidence for the disjunct distribution between Virginia and Missouri of the narrow endemic Helenium viginicum (Asteraceae). Journal of the Torrey Botanical Society 127: 316-323.

  • Simurda, M. C., D. Marshall and J. S. Knox. 2005. Phylogeography of the narrow endemic, Helenium virginicum (Asteraceae), Based on ITS sequence comparison. Systematic Botany 30(4): 887-898.

  • U.S. Dept. of Agriculture (USDA). 1979. Soil survey of Augusta County, Virginia. 249 pp. and maps.

  • U.S. Fish and Wildlife Service (USFWS. 2000. Virginia Sneezeweed (Helenium virginicum) Recovery Plan. Technical/Agency Draft. Hadley, Massachusetts. 54 pp.

  • U.S. Fish and Wildlife Service. 1998. Endangered and threatened wildlife and plants: 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. 1991. The status of populations of Helenium virginicum Blake (Asteraceae), a Virginia endemic sneezeweed. Virginia Journal of Science 42(2):179.

  • Werner, H.J. 1966. Geology of the Vesuvius quadrangle, Virginia. Virginia Division of Mineral Resources. Report #7.

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Citation for data on website including State Distribution, Watershed, and Reptile Range maps:
NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://explorer.natureserve.org. (Accessed:

Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Bird Range Maps of North America:
"Data provided by NatureServe in collaboration with Robert Ridgely, James Zook, The Nature Conservancy - Migratory Bird Program, Conservation International - CABS, World Wildlife Fund - US, and Environment Canada - WILDSPACE."

Citation for Mammal Range Maps of North America:
Patterson, B.D., G. Ceballos, W. Sechrest, M.F. Tognelli, T. Brooks, L. Luna, P. Ortega, I. Salazar, and B.E. Young. 2003. Digital Distribution Maps of the Mammals of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

Acknowledgement Statement for Mammal Range Maps of North America:
"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

Citation for Amphibian Range Maps of the Western Hemisphere:
IUCN, Conservation International, and NatureServe. 2004. Global Amphibian Assessment. IUCN, Conservation International, and NatureServe, Washington, DC and Arlington, Virginia, USA.

Acknowledgement Statement for Amphibian Range Maps of the Western Hemisphere:
"Data developed as part of the Global Amphibian Assessment and provided by IUCN-World Conservation Union, Conservation International and NatureServe."

NOTE: Full metadata for the Bird Range Maps of North America is available at:

Full metadata for the Mammal Range Maps of North America is available at:

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