Cuscuta epithymum - L.
Clover Dodder
Taxonomic Status: Accepted
Related ITIS Name(s): Cuscuta epithymum (L.) L. (TSN 30729)
Unique Identifier: ELEMENT_GLOBAL.2.144389
Element Code: PDCUS010K0
Informal Taxonomy: Plants, Vascular - Flowering Plants - Dodder Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Solanales Cuscutaceae Cuscuta
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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: Cuscuta epithymum
Conservation Status

NatureServe Status

Global Status: GNR
Global Status Last Changed: 22Mar1994
Rounded Global Status: GNR - Not Yet Ranked
Nation: United States
National Status: NNA
Nation: Canada
National Status: NNA (22Mar1994)

U.S. & Canada State/Province Status
United States California (SNA), Connecticut (SNA), Iowa (SNA), Kentucky (SNA), Maine (SNA), Maryland (SNA), Massachusetts (SNR), Michigan (SNA), Missouri (SNA), Montana (SNA), Nebraska (SNA), Nevada (SNA), New Jersey (SNA), New Mexico (SNA), New York (SNA), North Dakota (SNA), Ohio (SNA), Oregon (SNA), Pennsylvania (SNA), Rhode Island (SNA), South Dakota (SNA), Vermont (SNA), Virginia (SNA), Washington (SNA), West Virginia (SNA), Wyoming (SNA)
Canada British Columbia (SNA), New Brunswick (SNA), Ontario (SNA)

Other Statuses

NatureServe Global Conservation Status Factors

Other NatureServe Conservation Status Information

U.S. States and Canadian Provinces
Color legend for Distribution Map
NOTE: The distribution shown may be incomplete, particularly for some rapidly spreading exotic species.

U.S. & Canada State/Province Distribution
United States CAexotic, CTexotic, IAexotic, KYexotic, MA, MDexotic, MEexotic, MIexotic, MOexotic, MTexotic, NDexotic, NEexotic, NJexotic, NMexotic, NVexotic, NYexotic, OHexotic, ORexotic, PAexotic, RIexotic, SDexotic, VAexotic, VTexotic, WAexotic, WVexotic, WYexotic
Canada BCexotic, NBexotic, ONexotic

Range Map
No map available.

Ecology & Life History Not yet assessed
Economic Attributes Not yet assessed
Management Summary Not yet assessed
Population/Occurrence Delineation Not yet assessed
Population/Occurrence Viability
U.S. Invasive Species Impact Rank (I-Rank)
Disclaimer: While I-Rank information is available over NatureServe Explorer, NatureServe is not actively developing or maintaining these data. Species with I-RANKs do not represent a random sample of species exotic in the United States; available assessments may be biased toward those species with higher-than-average impact.

I-Rank: Medium/Insignificant
Rounded I-Rank: Unknown
I-Rank Reasons Summary: Dodders can negatively affect individual host plants, sometimes killing them. Dodders are also widespread and difficult to eradicate. However, they primarily invade lower quality disturbed native habitats and agricultural croplands.
Subrank I - Ecological Impact: Low/Insignificant
Subrank II - Current Distribution/Abundance: High/Medium
Subrank III - Trend in Distribution/Abundance: Medium/Insignificant
Subrank IV - Management Difficulty: High/Medium
I-Rank Review Date: 18May2004
Evaluator: Fellows, M.
Native anywhere in the U.S?
Native Range: Northern Africa, Temperate Asia, Middle East and Europe.

Download "An Invasive Species Assessment Protocol: Evaluating Non-Native Plants for their Impact on Biodiversity". (PDF, 1.03MB)
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Screening Questions

S-1. Established outside cultivation as a non-native? YES
Comments: (Kartesz 1999).

S-2. Present in conservation areas or other native species habitat? Yes
Comments: (WNPS 1997).

Subrank I - Ecological Impact: Low/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance/Insignificant
Comments: No ecosystem effects have been reported, therefore inferred to have a low or insignificant effect.

2. Impact on Ecological Community Structure:Medium/Low significance
Comments: Inferred - a vine that can be dense enough to smother the plant(s) it is climbing on (FLORIDATA 2004).

3. Impact on Ecological Community Composition:Medium/Low significance
Comments: Inferred - In a 2000 study in Slovakia, C. epithymum was found to parasitize crop plants (alfalfa) and some crop weeds - however, it has been shown to grow on up to 91 different hosts (Toth and Cagan 2001). May spread phytoplasma ('yellows disease') (Swift 2003).

4. Impact on Individual Native Plant or Animal Species:Unknown

5. Conservation Significance of the Communities and Native Species Threatened:Insignificant
Comments: Generally in disturbed areas (FLORIDATA 2004).

Subrank II. Current Distribution and Abundance: High/Medium

6. Current Range Size in Nation:High significance
Comments: Scattered and disjunct distribution in U.S., total area greater than 1/3, but from east to west coast, north to south borders (Kartesz 1999).

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Medium/Low significance
Comments: Kartesz (1999) lists Cuscuta epithymum as "noxious" in 5 of the 26 states, including California and Nevada. However, this is primarily an indication of the economic damage Cuscuta species in general can cause in agricultural situations. The degree of negative impacts to native plants and animals in more natural situations is uncertain. In Slovakia, this speices is found exclusively on alfalpha and incidentally on weeds growing the this crop (Toth and Cagan 2001) but it is found in old fields and the edges of woods in Pennsylvania (Rhoades and Klein 1995).

8. Proportion of Nation's Biogeographic Units Invaded:High significance
Comments: Given the wide distribution in Kartesz (1999), the species could occur in 55 eocregions - inferred from TNC (2001).

9. Diversity of Habitats or Ecological Systems Invaded in Nation:Low significance
Comments: Generally in disturbed areas (FLORIDATA 2004).

Subrank III. Trend in Distribution and Abundance: Medium/Insignificant

10. Current Trend in Total Range within Nation:Low significance/Insignificant
Comments: May spread slowly if at all (WNPS 1997).

11. Proportion of Potential Range Currently Occupied:Low significance
Comments: Inferred.

12. Long-distance Dispersal Potential within Nation:High/Moderate significance
Comments: Inadvertantly harvested and distributed with host plant, spread in hay, soil, water or animal manure (FLORIDATA 2004).

13. Local Range Expansion or Change in Abundance:Unknown

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Low significance/Insignificant
Comments: WNPS list B, wildland weed with low potential to spread (WNPS 1997).

15. Similar Habitats Invaded Elsewhere:Low significance
Comments: Present in Canada (Kartesz 1999).

16. Reproductive Characteristics:Moderate significance
Comments: Cuscuta spp. may produce 1000's of seed/plant which contribute to a long-lived seed bank, broken stems readily reattach to new hosts (FLORIDATA 2004).

Subrank IV. General Management Difficulty: High/Medium

17. General Management Difficulty:Moderate significance
Comments: Not easy - remove and burn all stems to prevent reinvasion(FLORIDATA 2004).

18. Minimum Time Commitment:High significance
Comments: Inferred long lived (~20+ years) seed bank.

19. Impacts of Management on Native Species:Moderate significance
Comments: Difficult to apply herbicides without killing vegetation underneath (Toth and Cagan 2001). Many rare Cuscuta spp. combined with the difficulty in determining which is a rare native vs. a common non-native could harm the rare natives(FLORIDATA 2004).

20. Accessibility of Invaded Areas:Unknown

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).

  • Floridata. 2004.10266 Rebel Circle, Tallahassee, Florida 32305. ONLINE Accessed, 2004.

  • 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.

  • 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.

  • Rhoads, A.F., and W.M. Klein, Jr. 1993. The vascular flora of Pennsylvania: Annotated checklist and atlas. American Philosophical Society, Philadelphia, PA. 636 pp.

  • Swift, C. J. 1996 (updated 2003). Cuscuta and Grammica species - Dodder A Plant Parasite. Colorado State University Cooperative Extension. ONLINE Accessed 2004, February.

  • The Nature Conservancy. 2001. Map: TNC Ecoregions of the United States. Modification of Bailey Ecoregions. Online . Accessed May 2003.

  • Toth, P. and L. Cagan. 2001. Spread of dodder (Cuscuta spp._ in the agroecosystems of Slovakia: Is it an emerging problem?. Proceedings of the International Scientific Coference on the Occasion of the 55th Anniversary of the Slovak Agriculutal Univerisity in Nitra, Acta fytotechnica et zootechnica, 4:117-120.

  • USDA, ARS, National Genetic Resources Program. 2001. Germplasm Resources Information Network - (GRIN). [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland.URL: (Accessed 2004)

  • Washington Native Plant Society (WNPS). 1997. Preliminary List of Exotic Pest Plants of Greatest Ecological Concern in Oregon and Washington. ONLINE. Accessed 2004, January.

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