Berberis canadensis - P. Mill.
American Barberry
Other Common Names: American barberry
Taxonomic Status: Accepted
Related ITIS Name(s): Berberis canadensis P. Mill. (TSN 18818)
Unique Identifier: ELEMENT_GLOBAL.2.156755
Element Code: PDBER02010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Barberry Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Ranunculales Berberidaceae Berberis
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Concept Reference
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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: Berberis canadensis
Conservation Status
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NatureServe Status

Global Status: G3G4
Global Status Last Reviewed: 17Jan2018
Global Status Last Changed: 17Jan2018
Ranking Methodology Used: Ranked by calculator
Rounded Global Status: G3 - Vulnerable
Reasons: There are over 200 occurrences known across the species range in Georgia, North Carolina, Tennessee, Virginia, and West Virginia, with disjunct remnant populations in Illinois, Indiana, Kentucky, and Missouri. The exact number is unknown, and more inventory and mapping may reveal more occurrences, even in Virginia. Most populations are small and have low reproduction. Further, Berberis canadensis is threatened range-wide as it is still targeted for eradication by agricultural officials. The federal program ended but states may still continue the program. Development is a threat to sites on private land. Succession of sites or encroachment of woody vegetation threatens many occurrences. Fire and infrequent mowing may benefit the species. Very little is known about threats and trends in Virginia where over half the occurrences are found, partially because it is fairly common. The eradication for this species in Virginia is not active.
Nation: United States
National Status: N3N4

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 Alabama (SH), Georgia (S1), Illinois (S1), Indiana (S1), Kentucky (S1), Maryland (SH), Missouri (S1), North Carolina (S2), Ohio (SNR), Pennsylvania (SX), South Carolina (SNR), Tennessee (S2), Virginia (S3S4), West Virginia (S1)

Other Statuses

NatureServe Global Conservation Status Factors

Range Extent Comments: Occurs in the southeastern United States: Georgia, North Carolina, Tennessee, Virginia, and West Virginia, with disjunct remnant populations in Illinois, Indiana, Kentucky, and Missouri. Considered extirpated from Alabama, Maryland, and Pennsylvania.

Area of Occupancy: 126-500 4-km2 grid cells
Area of Occupancy Comments:  

Number of Occurrences: 81 - 300
Number of Occurrences Comments: There are over 100 extant occurrences and likely over 200. In Kentucky, there is 1 but there are likely to be more occurrences (White, 1998). There are 2 in Georgia, 2 in Indiana, 13 in Missouri, 23 in North Carolina, and 44 in Tennessee. Ranked S3S4 in Virginia with occurrences in 19 counties and most likely over 100 occurrences (Johnny Townsend, pers. comm., January 2018).

Population Size Comments: Some populations have hundreds of plants, but most have low numbers of individuals (less than 50).

Number of Occurrences with Good Viability/Integrity: Unknown
Viability/Integrity Comments: There are sixteen occurrences documented as having good viability outside of Virginia but this has not been assessed in Virginia, where nearly half of the occurrences are found.

Overall Threat Impact: Medium - low
Overall Threat Impact Comments: Many occurrences, including those on private land, are threatened by encroachment of woody vegetation or succession of the habitat. Fire is one natural disturbance that maintained habitat for this species. 
Berberis canadensis (and the majority of barberries) is an alternate host for the black stem rust of wheat, oats, rye barley, and various wild and cultivated grasses (Weakley 1993, Steffey 1985, Rudolf 1974, Steyermark 1963). The U.S. Department of Agriculture and state agriculture offices initiated a comprehensive barberry eradication program in the past to eliminate black stem rust. As a result, numerous populations of this species were destroyed (Weakley 1993, Wiegman 1993, Homoya 1992, Steyermark 1963). The federal program ended but states may still continue the program.
Loss of primary habitat has also played a significant role in the demise of this species. The elimination of the natural fire regime has resulted in the succession of savanna and open woodland habitats into closed-canopy woodlands. Only in sites with extremely shallow soils or areas that are frequently mowed or cleared does B. canadensis persist in any significant populations. Since settlement, much of the available habitat has been destroyed, converted to cultivated fields, land development, and urbanization (Weakley 1993). These threats remain for extant populations.

Grazing is a potential threat to extant populations (Smith 1992, Ludwig 1993). Grazing may serve to maintain the open character of woodlands, but its effects on B. canadensis plants are unknown. In some areas, the plants appear to be grazed by cattle (Smith 1992). Soil compaction and disturbance may negatively impact individual plants and populations. Deer browsing plants is also a threat.
 
Competition from exotic plant species (such as Lonicera tatarica and Rhamnus cathartica) is a threat to populations (Ludwig 1993). These species can form dense stands and eliminate ground layer herbaceous and other shrub species, including B. canadensis. Excessive shading and canopy closure in woodlands may be a factor in reducing seed production in the species, as has been noted in Missouri (Smith 1992).

Short-term Trend: Decline of 10-30%
Short-term Trend Comments: The species has declined significantly since settlement due to habitat destruction and eradication efforts. Loss of the natural fire regime and continued eradication efforts suggest that the downward trend is continuing. 
Prior to eradication efforts in Indiana, Deam (1940) observed long stretches of the species along the banks of the Tippecanoe River, occupying an area "a few feet back from the edge of the bank and down the slope to high water mark".

Long-term Trend:  
Long-term Trend Comments: This species is historic in several states: Alabama, Illinois, Maryland, and Pennsylvania.

Berberis canadensis is known from Pennsylvania by one historic occurrence in the western portion of the state (Pennsylvania Natural Diversity Inventory-West 1993, Kunsman 1992). Habitat for the occurrence was listed as "woods and waste places around abandoned buildings" and "rocky woods" (Pennsylvania Natural Diversity Inventory-West 1993). There is some speculation whether the occurrence was native or was introduced to the site (Kunsman 1992).

Other NatureServe Conservation Status Information

Distribution
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Global Range: Occurs in the southeastern United States: Georgia, North Carolina, Tennessee, Virginia, and West Virginia, with disjunct remnant populations in Illinois, Indiana, Kentucky, and Missouri. Considered extirpated from Alabama, Maryland, and Pennsylvania.

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 AL, GA, IL, IN, KY, MD, MO, NC, OH, PAextirpated, SC, TN, VA, WV

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
AL Jefferson (01073)*, Lee (01081)*
GA Bartow (13015), Harris (13145)*, Meriwether (13199), Richmond (13245)*, Towns (13281)*
IL Jackson (17077)*, Tazewell (17179)*
IN Carroll (18015), White (18181)
KY McCreary (21147)
MO Shannon (29203), Texas (29215)
NC Alexander (37003)*, Buncombe (37021)*, Catawba (37035), Durham (37063), Granville (37077), Guilford (37081)*, Macon (37113), Madison (37115), McDowell (37111), Montgomery (37123), Orange (37135)*, Randolph (37151)*, Rockingham (37157), Rutherford (37161), Swain (37173)*, Transylvania (37175)*
PA Huntingdon (42061)*
TN Anderson (47001), Carter (47019), Claiborne (47025), Cumberland (47035), Fentress (47049)*, Franklin (47051), Grainger (47057), Greene (47059)*, Hawkins (47073), Johnson (47091), Knox (47093), Loudon (47105), Morgan (47129), Scott (47151), Sullivan (47163)*, Union (47173), Van Buren (47175), Washington (47179)*
WV Greenbrier (54025), Mercer (54055), Summers (54089)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
02 Raystown (02050303)+*
03 Middle Roanoke (03010102)+, Upper Dan (03010103)+, Upper Tar (03020101)+, Upper Neuse (03020201)+, Deep (03030003)+*, South Yadkin (03040102)+*, Upper Pee Dee (03040104)+, Upper Catawba (03050101)+, South Fork Catawba (03050102)+, Upper Broad (03050105)+, Seneca (03060101)+*, Middle Savannah (03060106)+*, Middle Chattahoochee-Lake Harding (03130002)+*, Middle Chattahoochee-Walter F. George Reservoir (03130003)+*, Upper Flint (03130005)+, Coosawattee (03150102)+, Locust (03160111)+*
05 Middle New (05050002)+, Greenbrier (05050003)+, Tippecanoe (05120106)+, South Fork Cumberland (05130104)+, Caney (05130108)+
06 South Fork Holston (06010102)+*, Watauga (06010103)+, Holston (06010104)+, Upper French Broad (06010105)+, Nolichucky (06010108)+*, Watts Bar Lake (06010201)+, Upper Little Tennessee (06010202)+, Upper Clinch (06010205)+, Powell (06010206)+, Lower Clinch (06010207)+, Emory (06010208)+, Hiwassee (06020002)+*, Sequatchie (06020004)+, Wheeler Lake (06030002)+, Upper Elk (06030003)+
07 Lower Illinois-Lake Chautauqua (07130003)+*, Upper Mississippi-Cape Girardeau (07140105)+*, Big Muddy (07140106)+*
11 Current (11010008)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: Shrub 3-20 dm tall; leaves elliptic-spatulate, spiny-serrate; yellow flowers.
General Description: American barberry is a sparsely branched shrub, 0.3-2 m tall with forked or trifid spines on its branches. Branchlets are brown, purple or reddish and rough-warty. The leaves are obovate to spatulate, 2-6 cm long, with non-distinct veinlets below, margins with up to 20 teeth, with thorns. The 5-10 flowers are in racemes up to 2-6 cm long. Flower petals are yellow, notched, 2.5-3.5 mm long with basal glands. The calyx is 8-11 mm wide with inner sepals 3-4 mm long. Fruits are ovoid, fleshy, scarlet berries, 5-7 mm long. (Gleason and Cronquist 1991, Mohlenbrock 1975).
Technical Description: A shrub 3-20 dm tall; leaflets mostly 3-6 cm long, the blades mainly spatulate, sometimes elliptic-spatulate or rarely oval, spiny-serrate; racemes 2-6cm long; calyx 8-11 mm wide, the inner sepals 3-4 mm long; petals yellow, mainly 2.5-3.5 mm long; berry scarlet, 5-7 mm long. (Small 1933).
Diagnostic Characteristics: Berberis canadensis is distinguished by having a raceme of 5-10 flowers with notched yellow petals (Gleason and Cronquist 1991).
Duration: PERENNIAL, Long-lived, DECIDUOUS
Reproduction Comments: Flowers April - May, fruits September - October (Radford et al. 1968, Chafin 2007).
Known Pests: American barberry and most other barberries are alternate hosts for wheat rust (Puccinia graminis), a fungus that has caused major losses in certain grain crops here and in Europe (Hill 2003).
Ecology Comments: American barberry is one of the few native shrubs that is not vulnerable to the effects of black walnut toxicity (Hill 2003).
Habitat Comments: Berberis canadensis occurs in open woods, on bluffs and cliffs and along river banks in the eastern and central United States (Gleason and Cronquist 1991, Cook et al. 1987, Fernald 1970, Small 1933). Formerly an inhabitant of savannas and open woodlands, fire suppression has significantly restricted its habitat to sites with shallow soil (such as glades and cliffs) or areas with mowing or other canopy-clearing activities (such as powerline corridors, railroad/road right-of-ways and riverbanks).

The single extant population from Indiana is restricted to steep banks along the Tippecanoe River in the northern part of the state (Homoya 1992). Associated plant species include Besseya bullii, Lithospermum sp. and liverworts (Indiana Natural Heritage Data Center 1989).

Historically, B. canadensis occurred in Maryland in dry, calcareous woodlands, open fields and serpentine barrens (Maryland Natural Heritage Program 1992).

In Missouri, B. canadensis is typically found on north-facing, rocky, wooded slopes; along streams; upper ledges or bluffs; exposed upper portions of bluffs on limestone, dolomite or sandstone; and mesic limestone/dolomite cliffs (Smith 1992, Roedner et al. 1978, Holt et al. 1974, University of Minnesota Herbarium (MIN)). Substrate composition usually consists of limestone, dolomite or sandstone with a somewhat basic pH (Smith 1993). Steyermark (1963) stated that the plant appears to be restricted to the edges of limestone bluffs where the soil is leached out, or near the contact point between chert or Roubidoux sandstone with limestone. Associated plant species in Missouri include Campanula rotundifolia, Carpinus caroliniana, Galium boreale ssp. septentrionale, Trautvetteria caroliniensis, and Zigadenus elegans (Smith 1992, Steyermark 1963).

Berberis canadensis is found in 19 mountain counties in southwest Virginia (Huber 1993). Occupied habitat includes dry, open woodlands over limestone, dolomite, richer sandstone or shale substrates, rocky and cliffy areas and open areas and glades with naturally thin soil (Ludwig 1993, Ludwig 1992). Associated plant species in glades include Helianthus divaricatus, Juniperus virginiana, and Schizachyrium scoparium. In rocky areas it is found with Cercis canadensis, Pellaea atropurpurea, and Quercus muehlenbergii (Ludwig 1993).

In North Carolina, B. canadensis occurs in the Piedmont on mafic rocks (such as diabase, amphibolite and gabbro) and in the Blue Ridge on calcareous (limestone, dolomite, marble) and mafic rocks (amphibolite). It generally occurs in glade, open woodland, bluff or cliff situations (North Carolina Natural Heritage 1993, Weakley 1993, University of Minnesota Herbarium (MIN)). The species was historically found in fire-maintained habitats which kept the canopy open, but is now restricted to sites with very shallow soil or with mowing maintenance (right-of-ways, powerline corridors, etc.). Due to its association with mafic and calcareous rocks (uncommon to rare in the state), B. canadensis is often associated with other rare species. Typical associated plant species include Aquilegia canadensis, Cercis canadensis, Clematis ochroleuca, Desmodium spp., Echinacea laevigata, Matelea decipiens, Parthenium auriculatum, Pycnanthemum spp., Rhus aromatica, Silphium trifoliatum, Solidago rigida, Symphoricarpos orbiculatus, and Viburnum rafinesquianum (North Carolina Natural Heritage 1993, Weakley 1993).

In Illinois, B. canadensis is known from a single extant site at the rim of a dry sandstone cliff (Illinois Natural Heritage Division 1992).

Collections at the University of Tennessee-Knoxville Herbarium (TENN) suggest that occupied habitat is relatively open woodlands (Pyne 1994). Collections have been made from wooded slopes, shale slopes, bluffs, terraces along river bluffs and river banks.

Economic Attributes
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Economic Comments: The primary threat to the survival of Berberis canadensis has been from the U.S. Department of Agriculture (USDA) comprehensive barberry eradication program. American barberry and most other barberries are alternate hosts for wheat rust (Puccinia graminis), a fungus that has caused major losses in certain grain crops here and in Europe (Hill 2003). Four small-grain crops (wheat, oats, barley, and rye) are all potential hosts to the organism causing black stem rust (BSR). Barberry is an alternate host for the organism causing black stem rust (BSR). Breeding varieties of small grains for resistance to BSR began in the United States around 1900 meeting with rapid success from crosses with wheat varieties from Russia and Turkey. By 1938, farmers were
planting resistant wheat varieties in the areas of the United States where BSR had been most destructive and continued to develop new resistant crop varieties. The difficulty with this approach is that while an individual crop variety may be resistant to several races of BSR, there are more than 200 existing races of BSR. The presence of BSR-susceptible barberry bushes providing the opportunity for new hybrid races of BSR to develop complicates the problem further. The use of resistant crops alone would never provide farmers with adequate protection from BSR. With the increasing demand for U.S. wheat, an alternative method of defense against a catastrophe the magnitude of the BSR epidemic of 1916 was needed.
In 1918, the U.S. Department of Agriculture (USDA) initiated a barberry eradication program in
cooperation with 13 north-central States (Colorado, Illinois, Indiana, Iowa, Michigan, Minnesota,
Montana, Nebraska, North Dakota, Ohio, South Dakota, Wisconsin, and Wyoming). In 1935, four
additional states (Missouri, Pennsylvania, Virginia, and West Virginia) joined the program, followed by Washington State in 1944. This time, the program resulted in the destruction of several hundred million susceptible barberry and mahonia bushes in over 700,000 square miles. Although barberry eradication is a cooperative project with State personnel, USDA has always played a leading role. USDA's funding for the barberry eradication program ended in 1980. Although several States continued some barberry eradication activities, the extensive eradication program also ended in 1980 (APHIS no date, Hill 2003).

Management Summary
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Stewardship Overview: Management for B. canadensis should include the use of prescribed fire, selective thinning of the canopy or controlled mowing in order to maintain high light levels and eliminate woody plant encroachment. Habitats need protection from urbanization, agricultural activities, destructive recreational activities, land development, indiscriminate pesticide application, excessive grazing and exotic species. Monitoring of occurrences should be conducted frequently to track their status with respect to management activities. Habitat quality should be monitored and an assessment of threats to all populations should be made. Cooperative efforts between state and federal regulatory agencies (e.g., USDA and state departments) should be exercised to reduce or eliminate the effects of continued Berberis eradication efforts. Research is needed to accurately assess the role of B. canadensis as an alternate host to stem rust. Investigations into the reproductive biology, genetic variation, pollination vectors, factors effecting seed production and the response to management activities are also needed.
Restoration Potential: The restoration potential of this species is largely unknown. Establishment or augmentation of populations is dependent upon seed germination, but conditions under which germination is triggered are unknown. Given success in germinating seeds, coupled with an active habitat management program designed to maintain open woodland/savanna conditions, restoration should be successful.
Preserve Selection & Design Considerations: Preserve designs should incorporate the requirements of fire management in maintaining suitable, open habitat. Preserve designs should incorporate sufficient area to conduct proper prescribed fire management and allow for a matrix of habitat areas and management units. Smoke planning should also be addressed in the preserve design.

Preserve size should also be a requirement for the long-term protection and viability of the species. Sufficient preserve size should be planned for habitat protection and restoration, and expansion of existing populations into these habitats.

Management Requirements: Berberis canadensis is a species of open woodlands, glades and savannas. Most of these habitats have grown closed with trees and shrubs since the elimination of a natural fire regime. Prescribed fire or selective thinning of the canopy should be conducted in order to increase light levels to the habitat and populations (Weakley 1993).

Managers should work cooperatively with state and federal regulatory agencies and organizations (e.g., USDA and state departments) to reduce or eliminate the effects of continued Berberis eradication efforts (Homoya 1992).

Monitoring Requirements: Long-term monitoring of known populations should be conducted every 1-2 years to track their status with respect to current management activities. Population monitoring efforts should include the counting of individuals present, determining the amount of yearly fruit/seed production and assessing recruitment rates. Habitat quality should be monitored as well as perceived threats to all populations (Weakley 1993, Smith 1992).

Management Programs: No known management programs are currently in place for the species in any portion of its range.
Monitoring Programs: Monitoring of plants is done by the Indiana DNR, Division of Entomology, for signs of black stem rust as part of eradication efforts.

Contact: Mike Homoya, Ecologist/Botanist, Indiana Natural Heritage Data Center, Division of Nature Preserves, Department of Natural Resources, 402 W. Washington St., Rm. W267, Indianapolis, IN 46204. Telephone: (317) 232-4052.

Populations in Missouri are revisited every several years in order to update their status in the Heritage Database. Most sites were revisited between 1984 and 1990.

Contact: Tim Smith, Botanist, Natural History Division, Missouri Department of Conservation, 2901 W. Truman Blvd., Jefferson, MO 65109. Telephone: (314) 751-4115.

Management Research Programs: No research programs directed at management needs are known at this time.
Management Research Needs: Research regarding the response of this species to fire, canopy thinning and other management activities would allow for better management of populations and habitat (Weakley 1993). There is a need to determine the best habitat for the species and how to best maintain the character of these areas (Smith 1992).
Additional topics: The red, fleshy berries of B. canadensis are edible (Small 1933). The plant is often grown for ornamental purposes because of its attractive foliage, flowers and fruit. It is also useful for wildlife food and cover and erosion control. The majority of barberry species are susceptible to black stem rust of wheat. Roots of barberry can be used to obtain a yellow dye. The plants contain an alkaloid called berberine, which is used for medicinal purposes in some areas (Rudolf 1974).

Research on this species has investigated the ultrastructural features of the cortical parenchyma cells in the stamen filaments (Fleurat-Lessard and Millet 1984). The stamen filaments of Berberis canadensis respond to various electrical, mechanical and chemical stimuli by bending. The mature stamens are formed from the reproductive meristem and lack photosynthetic activity and circadian movements. Berberis canadensis contains unusual walls, vascular microfibrils and microfilaments in the stamens. These walls are elastic due to their multiple folded appearance. Changes in the wall in the form of extensions may be linked with IAA, which may alter the fibrillar structure by regulating protein fluxes (Pilet and Roland 1974 as in Fleurat-Lessard and Millet 1984).

Another common name for this species is Alleghany barberry. An illustration of the species can be found in Steyermark (1963). Range distribution maps of the species can be found in the following sources: Missouri (Steyermark 1963), Virginia (Harvill et al. 1986).
Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 11Jan2018
NatureServe Conservation Status Factors Author: Ostlie, W. R. (MRO), 1998 update-S.L.Neid (MRO), rev. Treher (2018)
Management Information Edition Date: 10Feb1994
Management Information Edition Author: AMBROSE, DONN M. OSTLIE, WAYNE R. PENSKAR, MICHAEL R. SCHUEN, DAVID WALTER
Management Information Acknowledgments: We are indebted to all the botanists, ecologists, information managers and others who took the time to provide the information necessary for the preparation of this and many other Element Stewardship Abstracts.
Element Ecology & Life History Edition Date: 10Feb1994
Element Ecology & Life History Author(s): AMBROSE, DONN M.; OSTLIE, WAYNE R.; PENSKAR, MICHAEL R.; SCHUEN, DAVID WALTER ??

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).

References
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  • Aldrich, James R., et. al. 1986. The Discovery of Native Rare Vascular Plants in Northern Indiana. Indiana Academy of Science 95:421-428.

  • Chafin, L.G, J.C. Putnam Hancock, and H. Nourse. 2007. Field guide to the rare plants of Georgia. State Botanical Garden of Georgia, Athens, Georgia.

  • Cook, J. G., R. P. Lanka, J. L. Henszey, M. L. Neighbours, K. H. Dueholm, K. D. Kozie and S. H. Anderson. 1987. Species abstracts for federal rare animals. Section 5, Appendix 2 in literature reviews of rare species known to occur on National Park Service lands, Midwest Region. National Park Service, Midwest Regional Office, Omaha, Nebraska.

  • Deam, C. C. 1940. Flora of Indiana. Division of Forestry, Dept. of Conservation, Indianapolis, Indiana. 1236 pp.

  • Fernald, M. L. 1950. Gray's manual of botany. 8th edition. Corrected printing (1970). D. Van Nostrand Company, New York. 1632 pp.

  • Fleurat-Lessard, P. and B. Millet. 1984. Ultrastructural features of cortical parenchyma cells ('motor cells') in stamen filaments of Berberis canadensis Mills. and tertiary pulvini of Mimosa pudica L. J. Exp. Bot. 35(158):1332-1341.

  • Flora of North America Editorial Committee. 1997. Flora of North America north of Mexico. Vol. 3. Magnoliophyta: Magnoliidae and Hamamelidae. Oxford Univ. Press, New York. xxiii + 590 pp.

  • Gleason, H.A. 1952. The new Britton and Brown illustrated flora of the northeastern United States and adjacent Canada. 3 volumes. Hafner Press, New York. 1732 pp.

  • 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. Second edition. Virginia Botanical Associates, Farmville. 135 pp.

  • Herkert, J.R. 1991c. Endangered and Threatened Species of Illinois: Status and Distribution. Volume 1 - Plants. Illinois Endangered Species Protection Board.

  • Hill, S. R. 2003. Conservation Assessment for American Barberry (Berberis canadensis Mill.). Report prepared for the USDA Forest Service, Eastern Region, by the Illinois Natural History Survey. 7 March 2003. 39 pp. http://www.fs.fed.us/r9/wildlife/tes/ca-overview/docs/plant_Berberis_canadensis-AmericanBarberry.pdf

  • Holt, Francis T., et al., eds. 1974. Rare and Endangered Species of Missouri. Missouri Dept. of Conservation and Soil Conservation Service, no city, state. Unpaginated.

  • Jones, S. B., Jr., and N. C. Coile. 1988. The distribution of the vascular flora of Georgia. Department of Botany, University of Georgia, Athens.

  • Kartesz, J.T. 1993. Species distribution data for vascular plants of 70 geographical areas, from unpublished data files at the North Carolina Botanical Garden, July, 1993.

  • 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.

  • Martin, A. C., H. S. Zim, and A. L. Nelson. A. 1951. American wildlife and plants: A guide to wildlife food habits: The use of trees, shrubs, weeds, and herbs by birds and mammals of the U.S. Dover Publications, New York. 500 pp.

  • Mohlenbrock, R. H. 1975. Guide to the vascular flora of Illinois. Southern Illinois University Press, Carbondale. 494 pp.

  • Mohlenbrock, R.H. and K. Wilson. 1985. A floristic study of Fountain Bluff, Jackson County, Illinois. Erigenia 6:29-55.

  • Pilet, P.E. and J.C. Roland. 1974. Growth and extensibility of collenchyma cells. Plant Sci. Lett. 2:203-207.

  • Radford, A. E., H. E. Ahles, and C. R. Bell. 1964. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill, North Carolina.

  • Roberts, S.J. 1985. A note on Pseudomonas syrinagae pv. berberidis infections of BERBERIS: comparative infection studies in attached and detached leaves. J. App. Bact. 59:369-374.

  • Roberts, S.J. and T.F. Preece. 1984. A note on Pseudomonas syrinagae pv. berberidis infections of BERBERIS: Aetiology of the leaf spot and leaf fall disease in England. J. App. Bact. 56:507-513.

  • Roedner, B.J., D.A. Hamilton, and K.E. Evans. 1978. Rare plants of the Ozark Plateau: A field guide. U.S. Department of Agriculture Forest Service, North Central Forest Experiment Station, St. Paul, MN. 238 pp.

  • Rudolf, P.O. 1974. BERBERIS L., Barberry, Mahonia, in Agric. Handbook, U.S. Dept. Agric. 450:247-251.

  • Small, J.K. 1933. Manual of the southeastern flora. Two volumes. Hafner Publishing Company, New York.

  • Stedman, R. M. and R. L. Argyle. 1985. Rainbow smelt (Osmerus mordax) as predators on young bloaters (Coregonus hoyi) in Lake Michigan. J. Great Lakes Res. 11(1):40-42.

  • Steffey, J. 1985. Strange relatives: The barberry family. Am. Hort. 64(4):4-9.

  • Steyermark, J.A. 1963. Flora of Missouri. Iowa State Univ. Press, Ames. 1728 pp.

  • U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS). 2011. Barberry Inspection Manual. Accessed 2 August 2011. http://www.aphis.usda.gov/plant_health/plant_pest_info/barberry/downloads/manual.pdf.

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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:
http://www.natureserve.org/library/birdDistributionmapsmetadatav1.pdf.

Full metadata for the Mammal Range Maps of North America is available at:
http://www.natureserve.org/library/mammalsDistributionmetadatav1.pdf.

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