Hydrastis canadensis

L.

Goldenseal

G3Vulnerable (G3G4) Found in 14 roadless areas NatureServe Explorer →
G3VulnerableGlobal Rank
VulnerableIUCN
Very high - highThreat Impact
Identity
Unique IDELEMENT_GLOBAL.2.154701
Element CodePDRAN0F010
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
IUCNVulnerable
CITESAppendix II
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderRanunculales
FamilyRanunculaceae
GenusHydrastis
Other Common Names
goldenseal (EN) Hydraste du Canada (FR) Orangeroot (EN) Sceau d'or (FR) Yellow-puccoon (EN) Yellow Root (EN)
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.
Conservation Status
Rank MethodLegacy Rank calculation - Excel v3.1x
Review Date2012-11-30
Change Date2012-11-30
Edition Date2013-04-29
Edition AuthorsOliver, L.
Threat ImpactVery high - high
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences> 300
Rank Reasons
Goldenseal, Hydrastis canadensis, an herbaceous understory species of the eastern deciduous forest, with the core of its range in Indiana, Kentucky, Ohio and West Virginia (Sinclair and Catling 2000a). It extends north into Ontario, Canada and as far south in the United States to Alabama, east to North Carolina and north to Vermont.

Goldenseal may be best known for its use as an herbal supplement for a variety of health purposes, including as an immune booster and anti-inflammatory agent. Its earliest known use was by indigenous people in the eastern North America and by the 1700s it was used as a digestion aid and treatment for skin imflammation (Barton 1798). Its use is well documented from the 1800s to the present, with increasing demand through time as markets expanded beyond local usage. The species has been primarily wild-harvested, and over-collection of the plant is a predominate threat.

Concern due to over-collection is expressed at the national levels both in the United States and Canada. Since 1997, goldenseal has been listed in Appendix II of the Convention for International Trade on Endangered Species of Wild Fauna and Flora (CITES), to regulate international trade to ensure there is no detriment to the survival of the species in the wild. The CITES Appendix II listing requires that exporters obtain CITES permits or certificates for international export of whole, parts and powdered roots and rhizomes of goldenseal. In Canada, goldenseal is listed as Threatened on Schedule I of the federal Species at Risk Act.

Long-term decline since the beginning of its harvest history is evident, and short term trends are more localized, from declining to stable. State conservation statuses range from vulnerable to critically imperiled in the periphery of the range, to uncommon and secure in the core of its range. As of 2013, the species is state-listed as endangered, vulnerable or threatened in at least ten states. Seven of the states within goldenseal's range do not have State plant endangered species lists or protection laws.

Goldenseal, from a rangewide perspective and in a classical perspective of distribution and abundance is currently uncommon to secure, however, from a more holistic conservation perspective the extent of threats, long-term trends and short-term trends demand continuous and close monitoring in both the United States and Canada.
Range Extent Comments
Range extent was calculated based on a map in Sinclair and Catling (2000a). Range extent is closer to 1,250,000 sq km.

Eastern United States, northward into Ontario: southern Vermont to Ontario, west to Minnesota and south to Georgia, Alabama, and Arkansas. Common in Arkansas, Indiana, Illinois, Kentucky, Missouri, Ohio, and West Virginia; uncommon around the range perimeter. The central portion of its range is and was where goldenseal was the most abundant, including Indiana, Kentucky, Ohio, and West Virginia (Sinclair and Catling 2000a). Christensen and Gorchov (2010) describe the core part of the historical range as the Ohio River Valley.
Occurrences Comments
USA: 1000+ extant occurrences globally. Alabama: 14; Arkansas: 100s; Connecticut: 6, Delaware: 26;Georgia: 15; Kansas (no occurrences delineated), Kentucky: >100; Illinois: 100s; Indiana: 59; Iowa: 21; Massachusetts: 4, Maryland: 19; Michigan: 91; Minnesota: 14; Mississippi: 5; Missouri: 100s; New York: 22; North Carolina: 31; New Jersey: 2; Ohio: many; Pennsylvania: 17; Vermont: 5; Tennessee: 154; West Virginia: many; Wisconsin: >100 CANADA: Ontario (22) (NatureServe Element Occurrence data 2012). Element occurrence data not available for Virginia. Since many states do not actively track this species, and because it is clonal, population numbers are not well known. Arkansas, Kentucky, Illinois, Indiana, Missouri, Ohio, and West Virginia likely have the highest number of plants.
Threat Impact Comments
Hydrastis canadensis, Goldenseal, a medicinal herb, is threatened primarily by removal of habitat, decline in habitat quality, wild-collection and deer browsing.

Habitat destruction is a primary threat throughout its range, as reported by Sinclair and Catling (2000a) only 5% of forested habitat that supports goldenseal in Canada remains, in many personal communications with Natural Heritage Botanists in 2012 and throughout New England (Tait 2006). It is surmised that local extinctions in Ohio were the result of urban sprawl (Mulligan and Gorchov 2004). The interaction and compounding intensification of over-collection and habitat loss, should not be overlooked. Albrecht and McCarthy (2006) suggest that observations by botanists of population disappearance in the early 19th century documented this co-occurrence of threats. It is also suggested that the combination of these two threats may reduce or reverse positive efforts of stewardship, or 'managed' populations (Albrecht and McCarthy 2006). It should also be recognized that the combined interaction of these threats may be increasing the rate of decline in areas of its range where these two threats are actively occurring.


Goldenseal has been cultivated for 100+ years throughout its range and historically most of the trade domestically and internationally comes from wild harvested plants (Christensen and Gorchov 2010). In recent years there has been an apparent shift. The CITES Trade Database (200-2013) indicates that much of the material in international trade, and all in 2003, which is legal is from cultivated plants. The market for goldenseal is expected to grow at a rate of 5% to 10% annually, and the market for high quality cultivated material is expected to grow 10 to 15% annually (Greenfield and David 2012).

Cultivated goldenseal makes p a large portion of domestic trade according to the American Herbal Products Association (AHPA), however, the amount of wild-harvested rhizome that is collected and traded in the United States is unknown. In Indiana, collection pressure has intensified dramatically over the last 10 years, based on the number of inquiries by herbal diggers in the state (pers. comm. Indiana Department of Natural Resources). Along with the increased demand for goldenseal in Indiana, according to State officials, it is evident that herbal diggers that are harvesting wild goldenseal in July and August are also harvesting American ginseng (Panax quinquefolius) outside the legal harvest season that has not yet had a chance to reproduce (pers. comm. Indiana Department of Natural Resources). Law enforcement officials in Indiana are concerned for the species due to the amount being shipped from the state, and while there are no quantitative data on population declines in Indiana (pers. comm. Indiana Department of Natural Resources), declines seem likely. Collection pressure in parts of the species' range where unemployment is high is incentivized by prices paid for wild-collected roots/rhizomes in the herbal market (McGraw et al. 2003). Studies suggest that if as little as 10% of the plants from a population are removed by collected annually, that the population will go extinct over time (Mulligan and Gorchov 2004).

Invasive species is also a threat, including pressure from both non-native plants. White-tailed deer browse is also a threat in Ohio (Mulligan and Gorchov 2004) and in other parts of the range.

Further threats as noted by state Natural Heritage Botanists:
Alabama: Incompatible forestry practices appear to be the foremost concern, with invasive species of secondary importance (Al Schotz, pers. comm., 2012).
Arkansas: Unknown (Theo Witsell, pers. comm., 2012).
Connecticut: Invasive species and canopy closure. Severity of the threats is unknown (Nelson DeBarros & Nancy Murray, pers. comm., 2012).
Delaware: Invasive species and deer browse (William A. McAvoy, pers. comm., 2012).
Indiana: Not known, but collecting and habitat destruction likely (Michael Homoya, pers. comm., 2012).
Kansas: Unknown (Craig C. Freeman, pers. comm., 2012).
Kentucky: The current threats are land conversion/development, collection, and high deer populations (Deborah White, pers. comm., 2012).
Massachusetts: This plant has never been common in Massachusetts, populations are very small and threatened by herbivory (Bryan Connolly, pers. comm., 2012)
Michigan: Collecting and habitat destruction (M.R. Penskar et al. 2001).
Minnesota: Invasive species (such as garlic mustard and buckthorn) continue to be discovered in the greater area of goldenseal's range in Minnesota. This will likely be a rising threat to populations in the long-term (Derek Anderson, Welby Smith, & Nancy Sather, pers. comm., 2012).
Missouri: Current threats are over harvesting, particularly on public land. (Malissa Underwood, pers. comm., 2012).
Mississippi: In the Loess Bluff Physiographic Province, rapid subdivision development is encroaching into the habitat of goldenseal. One population has already probably been extirpated by a "Loess Bluff Restoration Project" associated with a housing development. In the Pontotoc Ridge Physiographic Province, the private land owner is considering developing the land as a new subdivision(Heather Sullivan, pers. comm., 2012).
New York: It is collected for medicinal purposes but so far there is no evidence that it is being over-collected in New York. There is a moderate threat from habitat destruction, especially in the Lower Hudson area. Exotic species like garlic mustard and bush honeysuckle threaten its understory habitat (Steve Young, pers. comm., 2012).
North Carolina: Poaching and effects of climate change (drought, increased temperatures, wind damage, invasive species) (Laura Gadd, pers. comm., 2012).
New York: It is collected for medicinal purposes but so far there is no evidence that it is being over-collected in New York. There is a moderate threat from habitat destruction, especially in the Lower Hudson area. Exotic species like garlic mustard and bush honeysuckle threaten its understory habitat (Steve Young, pers. comm. 2012).
Ohio: Some threats include development, recreation, roads and associated maintenance, resource extraction and processing (timber, oil, renewable energy), agriculture, and non-native species (Rick Gardner, pers. comm., 2012).
Ontario: Possibly lack of disturbance at some sites (Sinclair & Catling 1998) (Michael J. Oldham, pers. comm., 2012).
Pennsylvania: Invasive species, succession (more coming in later report), and gas development (Chris Firestone, pers. comm., 2012.)
Tennessee: Timber operations and ATV trails are the main threats (Todd Crabtree, pers. comm., 2012).
Virginia: Mostly unknown, but harvest and development are likely threats (John Townsend, pers. comm., 2012).
Vermont: Invasives, development, and climate change. (Bob Popp & Aaron Marcus, pers. comm., 2012).
Wisconsin: Forest conversion is likely the largest historical threat. Forest fragmentation and development is likely the largest current threat with invasive plants and earthworm likely causing significant impacts, especially for spread by seed. Leaf herbivory is unknown, but deer populations are high in the known region. Fruit herbivory and seed destruction is also unknown, but turkeys and rodents may be causing destruction of seed or placement in inappropriate habitat. Possible threats by logging, although the level of logging in the southern part of the state where it is found is relatively low, especially in the southeast. Impacts of harvest are unknown. We do not receive any harvest data and reports of sales to ginseng dealers is erratic. It would be fairly simple to survey ginseng dealers and ask them about amounts and trends in goldenseal harvest. Dealers may also have a sense if it is generally being harvested sustainably. (Kevin Doyle, Assistant Botanist & Ryan O'Connor, Assistant Ecologist, Kelly Kearns, pers. comm., 2012).

West Virginia: Wild harvest (P.J. Harmon, pers. comm., 2012).
Ecology & Habitat

Description

Goldenseal is a perennial plant that grows from stems one to two feet high. Plants with single leaves produce no flowers and plants with two leaves produce flowers (Van der Voort et al. 2003). The flowers are greenish-white, made up of three sepals and many stamens and carpels which emerge in April or May. Fruits ripen between July and August. Goldeneal produces a rhizome with many adventitious roots emerging from it. The rhizome is yellowish, growing horizontally, is knotty and grows between 4-7cm long and between 0.5-2cm in width (Sinclair and Catling 2000a).

Habitat

In the United States goldenseal is found in rich, densely shaded, deciduous forests with good air flow and water drainage (Greenfield and Davis 2012). Light gaps and soil disturbance stimulate local proliferation (McGraw et al. 2003).

Canada: In Southwest Ontario goldenseal is limited to deciduous woodlands near floodplains and periodic spring-flooded plateaus. There only remnants of this woodland remains, less than 5%of these forests remain from pre-settlement times (Sinclair and Catling 2000).

Goldenseal grows best in rich, mesic hardwood forest, especially those underlain by limestone or alkaline soils, but is also known from slightly acidic soils too. These forests are often second growth forests with the following associates (listed alphabetically by strata): Acer rubrum, Acer saccharum, Betula lenta, Carpinus caroliniana, Carya spp., Fagus grandifolia, Fraxinus americana, Liriodendron tulipifera, Ostrya virginiana, Quercus spp., Thuja occidentalis, Tilia americana, Ulmus rubra, Cornus alternifolia, Corylus americana, Lindera benzoin, Lonicera spp., Parthenocissus quinquefolia, Toxicodendron radicans, Adiantum pedatum, Anemone quinquefolia, Aralia nudicaulis, Arisaema triphyllum, Asarum canadense, Asplenium platyneuron, Asplenium rhizophyllum, Carex platyphylla, Carex spp., Caulophyllum thalictroides, Cimicifuga racemosa, Dicentra spp., Dryopteris spp., Geranium maculatum, Hepatica spp., Hydrophyllum spp., Maianthemum spp., Mitella diphylla, Osmorhiza spp., Panax quinquefolius, Podophyllum peltatum, Polystichum acrostichoides, Sanguinaria canadensis, Trillium spp., Uvularia spp., Viola spp. Species composition will vary considerable from region to region, but some of the above associates are likely to be found. Areas with Hydrastis also tend to have a nice collection of spring wildflowers and fern diversity is also likely higher than surrounding areas.

Reproduction

Goldenseal reproduces both clonally and sexually, with clonal division more frequent than asexual reproduction. It takes between 4 and 5 years for a plant to reach sexual maturity, i.e. the point at which it produces flowers. Plants in the first stage, when the seed erupts and cotyledons emerge, can remain in this state one or more years. The second vegetative stage occurs during years two and three (and sometimes longer) and is characterized by the development of a single leaf and absence of a well developed stem. Finally, the third stage is reproductive, at which point flowering and fruiting occurs. This last stage takes between 4 and 5 years to develop (Burkhart and Jacobson 2006).

Flowers in April through May, and fruits from June through July (Eichenberger and Parker 1976, Sinclair et al. 2000). Fruit and seed set is not dependent on cross-pollination because Goldenseal has a mixed-mating system and flowers show similar fruit set whether or not pollinators were excluded (Sanders 2004, Christensen and Gorchov 2010).
In the northern reaches of goldenseal's range, in southwest Ontario, seedlings are rare (Sinclair and Catling 2000a). A study in the core portion of the range, in Ohio, found that while seedlings were far fewer than ramets, a 'substantial' number of the seedling-minority made it to the next life history stage, and ultimately represents an infusion of genetic diversity into the otherwise highly clonal population (Christensen and Gorchov 2010).
Christensen and Gorchov (2010) noted the following that seedling rarity is not due to: a) infrequent flowering, low fruit or seed set, and low seed viability.

Christensen and Gorchov (2010) provide a good, clear diagram of the life-history of this plant, including diagrams of the possible transitions, places of regression to an earlier life stage, between life stages.
Terrestrial Habitats
Forest - Hardwood
Other Nations (2)
United StatesN3
ProvinceRankNative
KansasS1Yes
MassachusettsS1Yes
West VirginiaS3Yes
New YorkS2Yes
GeorgiaS2Yes
MississippiS1Yes
ConnecticutS1Yes
TennesseeS4Yes
New JerseyS1Yes
AlabamaS2Yes
VermontS1Yes
MichiganS2Yes
MinnesotaS1Yes
KentuckyS4Yes
DelawareS3Yes
IndianaS3Yes
IllinoisS4Yes
South CarolinaS1Yes
OhioS4Yes
VirginiaS3Yes
PennsylvaniaS4Yes
MarylandS2Yes
North CarolinaS3Yes
ArkansasS4Yes
MissouriS5Yes
IowaS3Yes
WisconsinS2Yes
CanadaN2
ProvinceRankNative
OntarioS2Yes
Threat Assessments
ThreatScopeSeverityTiming
1 - Residential & commercial developmentLarge (31-70%)Serious - moderateHigh (continuing)
5 - Biological resource useLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)
5.2 - Gathering terrestrial plantsLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)
5.3 - Logging & wood harvestingSmall (1-10%)Slight or 1-10% pop. declineHigh (continuing)
7 - Natural system modificationsRestricted (11-30%)Moderate or 11-30% pop. declineHigh (continuing)
8 - Invasive & other problematic species, genes & diseasesLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)
8.1 - Invasive non-native/alien species/diseasesLarge (31-70%)Moderate or 11-30% pop. declineHigh (continuing)

Plant Characteristics
DurationPERENNIAL, Long-lived
Economic Value (Genus)Yes
Roadless Areas (14)
Arkansas (5)
AreaForestAcres
Clifty CanyonOzark-St. Francis National Forest1,963
East ForkOzark-St. Francis National Forest13,037
Indian CreekOzark-St. Francis National Forest7,855
Pedestal RocksOzark-St. Francis National Forest21,957
Richland CreekOzark-St. Francis National Forest571
Illinois (2)
AreaForestAcres
Burden FallsShawnee National Forest485
Ripple HollowShawnee National Forest3,788
Indiana (1)
AreaForestAcres
Mogan RidgeHoosier National Forest8,435
North Carolina (3)
AreaForestAcres
Bald MountainPisgah National Forest11,085
South Mills RiverPisgah National Forest8,588
Woods MountainPisgah National Forest9,602
Virginia (2)
AreaForestAcres
Adams PeakGeorge Washington National Forest7,135
Price MountainJefferson National Forest9,119
West Virginia (1)
AreaForestAcres
Cheat MountainMonongahela National Forest8,191
References (100)
  1. Albrecht, M. A. and B. C. McCarthy. 2006. Comparative analysis of Goldenseal (<i>Hydrastis canadensis</i> L.) population re-growth following human harvest: implications for conservation. The American Midland Naturalist 156(2): 229-236.
  2. Anderson, Derek. Personal communication. Botanist. Minnesota Natural Heritage & Nongame Research.
  3. Bailey, B. 1999. Social and economic impacts of wild harvested products. Ph.D. Dissertation, West Virginia University, Morgantown, West Virginia.
  4. Baker, D. 2010. Goldenseal pays off for La Center's Sego's Herb Farm. Oregonian, September 17. Available online: http://www.oregonlive.com/clark-county/index.ssf/2010/09/goldenseal_pays_off_for_la_centers_segos_herb_farm_farm.html. Available December 2012
  5. Bannerman, J. 1997. The goldenseal dilemma: Saving the plant that heals. The Institute of Conservation & Culture, New Orleans, Louisiana. Manuscript in preparation.
  6. Barton, B.S. 1798 &amp; 1804. Collections for An Essay Towards A Materia Medica of the United States. Reprint ed. 1900. Bulletin of the Lloyd Library, No. 1, Reproduction Series, No. 1.
  7. Benigni, R., et al. 1962. Piante Medicinali-Chimica, Farmacologia e Terapia, Vol. 1. Inverni & Della Beffa, Milan.
  8. Bradley, P., ed. 1992. British Herbal Compendium, Vol. 1. British Herbal Medical Association, Dorset, U.K.
  9. Brevoort, P. 1996. The U.S. botanical market: An overview. HerbalGram No. 36: 49-57.
  10. Burkhart, E. and M. Jacobson. 2006a. Nontimber forest products(NTFPs) from Pennsylvania. Goldenseal, <i>Hydrastis canadensis.</i> Penn State College of Agricultural Sciences.Publications Distribution Center, The Pennsylvania State University, 112 Agricultural Administration Building, University Park, PA 16802. 16 pp.
  11. Burkhart, E. P. and M. G. Jacobson. 2009. Transitioning from wild collection to forest cultivation of indigenous medicinal forest plants in eastern North America is constrained by lack of profitability. Agroforest Syst. 76: 437-453.
  12. Catling, P.M. and Small, E. 1994. Poorly known economic plants of Canada. 3. Hydrastis canadensis L. CBA/ABC Bull. 27(3): 50-51.
  13. Christensen, D. L. and D. L. Gorchov. 2010. Population dynamics of goldenseal (<i>Hydrastis canadensis</i>) in the core of its historical range. Plant Ecology 210: 195-211.
  14. CITES. 1997. Amendments to Appendices I and II of the Convention on Internation Trade in Endangered Species and Wild Fauna and Flora. Online. http://international.fws.gov/cop10/gseal97.html. 14 January 2000.
  15. Connolly, Bryan. Personal communication. State Botanist, Massachusetts Natural Heritage and Endangered Species Program.
  16. Crabtree, Todd. Personal communication. Botanist, Tennessee Division of Natural Areas, Tennessee Department of Environmental Conservation, Nashville, TN.
  17. Crow, G.E. 1982. New England's rare, threatened, and endangered plants. USWFS Northeast Region, Newton Corners, MA.
  18. Deam, C. C. 1940. Flora of Indiana. Division of Forestry, Dept. of Conservation, Indianapolis, Indiana. 1236 pp.
  19. DeBarros, Nelson. Personal communication. Plant Ecologist, Wildlife Division, Bureau of Natural Resources, Connecticut Department of Energy and Environmental Protection, Hartford, CT.
  20. Dodds, J.S. 2024. <i>Hydrastis canadensis</i> Rare Plant Profile. New Jersey Department of Environmental Protection, State Parks, Forests & Historic Sites, Forests & Natural Lands, Office of Natural Lands Management, New Jersey Natural Heritage Program, Trenton, NJ. 22 pp. [https://www.nj.gov/dep/parksandforests/natural/heritage/docs/hydrastis-canadensis-golden-seal.pdf]
  21. Douglas, J. A., J. M. Follett, G. A. Parmenter, C. E. Sansom, N. B. Perry, R. A. Littler. 2010a. Seasonal variation of biomass and bioactive alkaloid content of goldenseal, <i>Hydrastis canadensis.</i> Fitoterapia (7): 925-928.
  22. Doyle, Kevin. Personal communication. Acting Botanist, Natural Heritage Inventory, Bureau of Endangered Resources, Wisconsin Department of Natural Resources.
  23. Egert, J. L. (Jan. 2007). "<i>Hydrastis canadensis</i>." Plant Conservation Alliance-Medicinal Plant Working Group. Arlington, Virginia. http://www.plantconservationwiki.org/wiki/Hydrastis_canadensis [April 26, 2013]
  24. Eichenberger, M. D. and G. R. Parker. 1976. Goldenseal (<i>Hydrastis canadensis</i> L.) distribution, phenology and biomass in an oak-history forest. Ohio Journal of Science 76(5): 204-210.
  25. Elliott, D. 1995. Wild Roots: A Forager's Guide to the Edible and Medicinal Roots, Tubers, Corms, and Rhizomes of North America. Healing Arts Press, Rochester, Vermont. Pp. 30-31.
  26. Fernald, M. L. 1950. Gray's manual of botany. 8th edition. Corrected printing (1970). D. Van Nostrand Company, New York. 1632 pp.
  27. Firestone, Chris. Personal communication. Botanist. Pennsylvania Natural Heritage Program.
  28. Flora of North America Editorial Committee (FNA). 1997. Flora of North America north of Mexico. Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press, New York. xxiii + 590 pp.
  29. Foster, S. 1991. Goldenseal, Hydrastis canadensis. American Botanical Council, Botanical Series No. 309. 8 pp.
  30. Foster, S. 1995. Forest Pharmacy: Medicinal Plants in American Forests. Forest History Society, Durham, North Carolina.
  31. Freeman, Craig. Personal communication. Botanist, Kansas Natural Features Inventory. Kansas Biological Survey, Lawrence, KS.
  32. Frontier Natural Products Co-op. 2012. Website available online: www.frontiercoop.com/wellearth/explorebyproduct/goldenseal.php. Accessed 17 Dec 2012.
  33. Gadd, Laura. Botanist North Carolina Plant Conservation Program. Personal Communication.
  34. Gardner, Rick. Personal communication. Heritage Botanist, Ohio Natural Heritage Program, Division of Natural Areas & Preserves, Ohio Department of Natural Resources, Columbus, OH.
  35. Geyer, W. A., R. Janke, C. J. Barden, and E. Carey. 2008. Ginseng (<i>Panax quinqufolius </i>L.) and goldenseal (<i>Hydrastis canadensis</i> L.) trials in eastern Kansas. Transactions of the Kansas Academy of Science 111(1/2): 147-152.
  36. Gleason, H.A. 1968. The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada. Vol. 3. The Sympetalous Dicotyledoneae. Hafner Publishing Co., Inc., New York.
  37. Gorchov, David L. Professor, Miami University: Department of Botany, Oxford, OH,
  38. Greenfield, J. and J. Davis. 2012. Goldenseal (<i>Hydrastis canadensis </i>L.). NC State University. A revision of a manuscript published in 2004 for the NC Consortium on Natural Medicines, a GoldenLEAF Foundation funded project of the University of North Carolina, Chapel Hill and NC State University. Available at: http://www.naturalmedicinesofnc.org.
  39. Grieve, M. 1971. A Modern Herbal, Vol. 1-2. Dover Publications Inc., New York, New York. 888 p.
  40. Harmon, P.J. Botanist, West Virginia Natural Heritage Program, Department of Natural Resources Operations Center, Elkins, WV.
  41. Henkel, A., and G.F. Klugh. 1904. Golden seal. U.S. Dept. Agric., Bureau of Plant Industry, Bull. No. 51, Part 6. 16 pp.
  42. Hill, A.F. 1952. Economic Botany, 2nd edition. McGraw-Hill Book Co., New York. 560 pp.
  43. Homoya, Mike. Personal communication. Botanist/Plant Ecologist. Indiana Department of Natural Resources, Division of Nature Preserves. Indianapolis, IN.
  44. Indiana Department of Natural Resources, Division of Nature Preserves. Indianapolis, IN
  45. Inoue, M, K. J. Kelley, A. Frary, and L.E. Craker. 2013. A measure of genetic diversity of Goldenseal (<i>Hydrastis canadensis</i> L.) by RAPD analysis. Genetic Resources and Crop Evolution.60(3): 1201-1207.
  46. Kaneda, Y. 1991. In vitro effects of berberine sulfate on the growth of Entamoeba histolytica, Giardia lamblia and Tricomonas vaginalis. Ann. Trop. Med. Parasitol. 85: 417-425.
  47. 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.
  48. Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First edition. In: Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill, N.C.
  49. Kauffman, G. 1996. Biological White Paper on Hydrastis canadensis. North Carolina. Manuscript in preparation.
  50. Kearns, Kelly. Personal communication. Conservation Biologist. Natural Heritage Inventory, Bureau of Endangered Resources, Wisconsin Department of Natural Resources.
  51. Kelley, K. J. 2009a. Genetic variability in <i>Hydrastis canadensis</i> L. using RAPD analysis. A thesis presented to the Graduate School of the University of Massachusetts Amherst, Department of Plant &amp; Soil Science. 27 pp.
  52. Liu, C.X. 1991. Studies on plant resources, pharmacology and clinical treatment with berberine. Phytother. Res. 5: 228-230.
  53. Lloyd, J.U. and C.G. Lloyd. 1884-1885. Drugs and Medicines of North America, Vol. 1, Ranunculaceae. Clarke, Cincinnati, Ohio. 304 pp.
  54. Lloyd, J.U., and C.G. Lloyd. 1908. <i>Hydrastis canadensis</i>. Bull. Lloyd Library of Botany, Pharmacy and Materia Medica 10. 184 pp.
  55. Mahady, G. B., and L. R. Chadwick. 2001. Goldenseal (<i>Hydrastis canadensis</i>): Is There Enough Scientific Evidence to Support Safety and Efficacy? Nutrition in Clinical Care 4(5):243-249.
  56. Marcus, Aaron. Personal communication. Botanist, Vermont Nongame & Natural Heritage Program.
  57. McAvoy, Bill. Personal communication. Botanist, Delaware Natural Heritage Program.
  58. McGraw, J. B., S. M. Sanders, and M. Van der Voort. 2003. Distribution and abundance of <i>Hydrastis canadensis</i> L. (Ranunculaceae) and <i>Panax quiquefolius</i> L. (Araliaceae) in the central Appalachian region. Journal of the Torrey Botanical Society 130(2): 62-69.
  59. McGuffin, Michael. Personal communication. American Herbal Products Association, Silver Spring MD
  60. McGuffin, M., on behalf of American Herbal Products Association (AHPA). 11 June 2012. Comments of the American Herbal Products Association on the request for comments and information on species proposals for consideration at the 16th Conference of the Parties to CITES. Available online: www.ahpa.org/portals/0/pdfs/12_0611_AHPA_Comments_reCoP16.pdf. Accessed December 2012.
  61. Medical Sciences Bulletin. 1996 (Oct.). Treatment Options for HIV: The Health Food Store Connection. Online: PharmInfoNet Home Page.
  62. Mills, S.Y. 1991. Out of the Earth: The Essential Book of Herbal Medicine. Viking, London. Pp. 439-441. Millspaugh, C.F. 1887 [1974]. American Medicinal Plants. Dover Publications, New York, p. 9-2.
  63. Morse, Larry E. Personal Communication. North American Botanist, NatureServe, Arlington, VA. Formerly Chief Botanist, The Nature Conservancy, Arlington, VA.
  64. Mulligan, M. R. and G. L. Gorchov. 2004. Populations loss of goldenseal, <i>Hydrastis canadensis</i> L. (Ranunculaceae), in Ohio. Journal of the Torrey Botanical Society 13(24): 305-310.
  65. Murray, M. 1995. The Healing Power of Herbs. Prima, Rocklin, Calif. Pp. 162-172.
  66. Murray, Nancy. Personal communication. Coordinator, Connecticut Natural Diversity Database.
  67. National Center for Complementary and Alternative Medicine (NCCAM). 2012. Available online: http://nccam.nih.gov/health/goldenseal#science. Accessed 2012.
  68. O'Connor, Ryan. Personal communication. Ecologist/Inventory Coordinator, Natural Heritage Inventory, Bureau of Endangered Resources, Wisconsin Department of Natural Resources.
  69. Oldham, Michael. Personal communication. Botanist, Ontario Natural Heritage Information Centre.
  70. Pennsylvania Department of Conservation and Natural Resources (PA DCNR). 2012. <i>About goldenseal</i>. Available online: www.dcnr.state.pa.us/forestry/wildplant/aboutgoldenseal.aspx. Accessed December 2012.
  71. Penskar, Mike. Personal communication. Botanist, Michigan Natural Features Inventory. Lansing, MI.
  72. Penskar, M.R, E.G. Choberka, and P.J. Higman 2001. Special Plant Abstract for <i>Hydrastis canadensis</i> (goldenseal). Michigan Natural Features Inventory. Lansing, MI. 3 pp.
  73. Planet Herbs. 1999. Planet Herbs: Natural botanicals wholesale. Online. Available: http://www.planetherbs.net. Accessed 2000-Jan.
  74. Popp, Robert. Personal communication. Botanist, Vermont Nongame and Natural Heritage Program, Vermont Fish and Wildlife Department, Barre, VT.
  75. Sack, R.B. and Froehlich, J.L. 1982. Berberine inhibits intestinal secretory response of Vibrio cholerae toxins and E. coli enterotoxins. Infect. Immun. 35: 471-475.
  76. Sanders, S. 2004. Does breeding system contribute to rarity of Goldenseal (<i>Hydrastis canadensis</i>)? American Midland Naturalist 152: 37-42.
  77. Sanders, S. and J. B. McGraw. 2005. Harvest recovery of Goldenseal, <i>Hydrastis canadensis</i> L. The American Midland Naturalist 153(1): 87-94.
  78. Sather, Nancy. Personal communication. Botanist/Ecologist. Minnesota Natural Heritage & Nongame Research.
  79. Schery, R.W. 1972. Plants for Man, 2nd edition. Prentice-Hall, Englewood Cliffs, New Jersey. 657 pp.
  80. Schotz, Al. Personal Communication. Botanist, Alabama Natural Heritage Program.
  81. Sinclair, A. and P. M. Catling. 2000a. Status of Goldenseal, <i>Hydrastis canadensis</i> (Ranunculaceae), in Canada. The Canadian Field Naturalist 114(1): 111-120.
  82. Sinclair, A. and P. M. Catling. 2000b. Ontario Goldenseal, <i>Hydrastis canadensis</i>, populations in relation to habitat size, paths and woodland edges. Canadian Field-Naturalist 11(4): 652-655.
  83. Sinclair, A. and P. M. Catling. 2002. Recent trends in stem number in Goldenseal, <i>Hydrastis canadensis</i>, populations at the northern limit of its range. Canadian Field-Naturalist 116(1): 112-115.
  84. Sinclair, A., P. M. Catling, and L. Dumouchel. 2000. Notes on the pollination and dispersal of Goldenseal, <i>Hydrastis canadensis </i>L., in southwestern Ontario. Canadian Field Naturalist 114(3): 499-501.
  85. Smith, Tim. Personal communication. Botanist, Missouri Department of Conservation. Missouri Department of Conservation, Jefferson City, MO
  86. Smith, Welby R. Personal communication. Botanist, Minnesota Natural Heritage Program, Minnesota Dept. Natural Resources, St. Paul, MN.
  87. Sullivan, Heather. Personal communication. Botanist, Mississippi Natural Heritage Program, Mississippi Museum of Natural Science, Jackson, MS.
  88. Sun, D. 1988. Berberine sulfate blocks adherence of Streptococcus pyogenes to epithelial cells, fibronectin, and hexadecane. Antimicrob. Agents Chemother. 32: 1370-1374.
  89. Tait, C. R. 2006a. Spatial distribution and habitat preference of Goldenseal, (<i>Hydrastis canadensis) </i>in New York state. M.S. Thesis - State University of New York, College of Environmental Science and Forestry, Syracuse, N.Y.
  90. Tobe, H. 2003a. Hydrastidaceae. In: Kubitzki, K. and C. Bayer. Flowering Plants Dicotyledons Vol. 5. Springer, Frankfurt, Germany. 438 pp.
  91. Torgerson, J. M. 2012a. Genetic variation in <i>Hydrastis canadensis </i>populations in western North Carolina. M.S. thesis, Western Carolina University. 61 pp.
  92. Townsend, J. Personal communication. Staff Botanist. Virginia Division of Natural Heritage. Department of Conservation and Recreation. Richmond, VA.
  93. Underwood, Malissa. Personal communication. Botanist. Missouri Natural Heritage Program.
  94. Van der Voort, M. E., B. Bailey, D. E. Samuel, and J. B. McGraw. 2003. Recovery of populations of Goldenseal (<i>Hydrastis canadensis</i> L.) and American Ginseng (<i>Panax quinquefolius</i> L.) following harvest. The American Midland Naturalist 149(2): 282-292.
  95. Veninga, L. and B. Zaricor. 1976. Goldenseal/Etc: A Pharmacognosy of Wild Herbs. Ruka Publications, Santa Cruz.
  96. Weakley, A.S., and Southeastern Flora Team. 2024. Flora of the southeastern United States. Edition of March 4, 2024. University of North Carolina Herbarium (NCU), North Carolina Botanical Garden, University of North Carolina, Chapel Hill. 2203 pp.
  97. White, Deborah. Personal communication. Botanist, Kentucky Nature Preserves Commission, Frankfort, KY.
  98. Witsell, Theo. Personal communication. Botanist. Arkansas Natural Heritage Commission. Little Rock, AR.
  99. Wofford, B.E. 1989. Guide to vascular plants of the Blue Ridge. University of Georgia Press. Athens, Georgia.
  100. Young, Steve. Personal communication. Botanist, New York Natural Heritage Program.