Chondrilla juncea - L.
Rush Skeletonweed
Other English Common Names: Hog Bite
Taxonomic Status: Accepted
Related ITIS Name(s): Chondrilla juncea L. (TSN 37029)
Unique Identifier: ELEMENT_GLOBAL.2.135667
Element Code: PDAST26010
Informal Taxonomy: Plants, Vascular - Flowering Plants - Aster Family
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Asterales Asteraceae Chondrilla
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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: Chondrilla juncea
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 (12Oct2016)

U.S. & Canada State/Province Status
United States California (SNA), Delaware (SNA), District of Columbia (SNA), Georgia (SNR), Idaho (SNA), Indiana (SNA), Maryland (SNA), Michigan (SNA), Montana (SNA), Nevada (SNA), New Jersey (SNA), New York (SNA), Oregon (SNA), Pennsylvania (SNA), Virginia (SNA), Washington (SNA), West Virginia (SNA), Wyoming (SNA)
Canada British Columbia (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, DCexotic, DEexotic, GA, IDexotic, INexotic, MDexotic, MIexotic, MTexotic, NJexotic, NVexotic, NYexotic, ORexotic, PAexotic, VAexotic, WAexotic, WVexotic, WYexotic
Canada BCexotic, ONexotic

Range Map
No map available.

U.S. Distribution by County Help
State County Name (FIPS Code)
NV Carson City (32510)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
16 Upper Carson (16050201)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
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: Chondrilla juncea is known as a noxious weed in cultivated and agricultural habitats but it also appears to have a limited, but measurable, impact in native species habitats. Most of the negative impacts are a result of a very deep tap root allows for persistence, as well as ability to remove moisture and nutrients from the root zone. It's impressive reproductive ability, through both vegetative and seed ensure a large supply of propagules. It does appear to be limited to very disturbed areas.
Subrank I - Ecological Impact: Low/Insignificant
Subrank II - Current Distribution/Abundance: Medium/Insignificant
Subrank III - Trend in Distribution/Abundance: Medium
Subrank IV - Management Difficulty: Medium/Low
I-Rank Review Date: 25Aug2004
Evaluator: Fellows, M.
Native anywhere in the U.S?
Native Range: Native to Eurasia, the native range centers on the Balkans (NWCB 2003). The range is from southern Russia to North Africa, and from Portugal to Turkey and Iran (NWCB 2003).

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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: Primarily a weed of waste places and roadsides (NWCB 2003; various flora), C. juncea is also found on public lands (e.g., near Grand Canyon National Park, Colorado State (APRS 2001)) and in rangelands.

Subrank I - Ecological Impact: Low/Insignificant

1. Impact on Ecosystem Processes and System-wide Parameters:Low significance
Comments: May affect water (APRS 2001) and nutrient availability for native plants (CDFA 2004).

2. Impact on Ecological Community Structure:Medium/Low significance
Comments: Herbaceous perennial to 4 feet tall and a tap root to 7 feet, or more (NWCB 2003).

3. Impact on Ecological Community Composition:Low significance
Comments: May reduce community diversity by outcompetong natives or limiting germination of natives (APRS 2001).

4. Impact on Individual Native Plant or Animal Species:Not ranked

5. Conservation Significance of the Communities and Native Species Threatened:Low significance/Insignificant
Comments: Disturbed anthropogenic habitats (irrigated lands, rangelands, roadsides) (NWCB 2003).

Subrank II. Current Distribution and Abundance: Medium/Insignificant

6. Current Range Size in Nation:Medium/Low significance
Comments: Kartesz (1999) reports Chondrilla juncea from 5 western and scattered eastern states. Reported to be uncommon in California (CDFA 2004), however it is known to infest several million acres in Idaho, California and the Pacific Northwest (Callihan and Miller 1999.

7. Proportion of Current Range Where the Species is Negatively Impacting Biodiversity:Low significance/Insignificant
Comments: Kartesz (1999) reports Chondrilla juncea as noxious from 5 western states, but merely present in the eastern states. The predominant impacts are in agriculture and rangelands (NWCB 2003).

8. Proportion of Nation's Biogeographic Units Invaded:Medium/Low significance
Comments: Inferred from Kartesz (1999), TNC (2001) and NRCS (2004), Chondrilla juncea probably occurs in at least 12 ecoregions and most likely more.

9. Diversity of Habitats or Ecological Systems Invaded in Nation:High/Moderate significance
Comments: Disturbed anthropogenic habitats (irrigated lands, rangelands, roadsides) (NWCB 2003).

Subrank III. Trend in Distribution and Abundance: Medium

10. Current Trend in Total Range within Nation:Moderate significance
Comments: Populations are expanding in the US, especially northward (NWCB 2003).

11. Proportion of Potential Range Currently Occupied:Low significance
Comments: Ideal habitat is limited to well-drained soils in climates with cool winters and hot, dry summers without prolonged drought (CDFA 2004).

12. Long-distance Dispersal Potential within Nation:High/Moderate significance
Comments: The pappus on each seed allows the seed to be carried up to 20 miles by wind currents (NWCB 2003). Contaminated farm equipment can take seeds and root fragments long distances (NWCB 2003).

13. Local Range Expansion or Change in Abundance:Medium/Low significance
Comments: One plant can colonize an area through vegetative reproduction (NWCB 2003), but only at a moderate rate (APRS 2001).

14. Inherent Ability to Invade Conservation Areas and Other Native Species Habitats:Low significance
Comments: Establishes in crop lands and cultivated lands (NWCB 2003) with little invasion in native communities (APRS 2001).

15. Similar Habitats Invaded Elsewhere:Low significance
Comments: Present in Canada (Kartesz 1999) and Australia in similar habitats (NWCB 2003). Also present in South America, New Zealand and Europe (NWCB 2003).

16. Reproductive Characteristics:High significance
Comments: A healthy plant can produce 1500 flower heads with the capability of producing 20000 viable seeds (NWCB 2003). Where sexual reproduction is prevented, the plant can regrow from root fragments (NWCB 2003). Some seeds may remain viable up to 5 years in the seed bank (APRS 2001).

Subrank IV. General Management Difficulty: Medium/Low

17. General Management Difficulty:Moderate significance
Comments: A 1-cm section of the extensive and deep tap and lateral root system can resprout aerial parts if damaged (NWCB 2003). Herbicides can be effective, especially with repeat follow-up treatments; however, several different biotypes of Chondrilla juncea have evolved, some of which are herbicide resistant (NWCB 2003). Fertilizer applications to increase competitive ability of desirable plants can be successful in reducing the number of Chondrila juncea, although individual C. juncea may be larger (NWCB 2003). Biocontrol agents can be useful, but success depends on the biotype of C. juncea (NWCB 2003). Infestations in California have been controlled and eradicated (CDFA 2004).

18. Minimum Time Commitment:Medium/Low significance
Comments: Treatments require follow-up applications because of the very deep root system (NWCB 2003). Infestations in California were successfully eradicated (CDFA 2004).

19. Impacts of Management on Native Species:Medium/Low significance
Comments: Herbicide use could result in non-target damage.

20. Accessibility of Invaded Areas:Not ranked

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).

  • Alien plants ranking system (APRS) Implementation Team. 2001a. Alien plants ranking system version 7.1. Southwest Exotic Plant Information Clearinghouse, Flagstaff, AZ. Online. Available: (accessed 2004).

  • California Department of Food and Agriculture. 2004. Noxious weed index sorted by scientific name - factsheets. Available: (Accessed 2004).

  • Callihan, R. H., and T. W. Miller. 1999. Idaho's Noxious Weeds. (revised by Don W. Morishita and Larry W. Lass). University of Idaho. Online. Available: (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.

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

  • USDA, NRCS. 2004. The PLANTS Database, Version 3.5 ( . National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

  • Washington State Noxious Weed Control Board (NWCB). 2003. Written Findings of the State Noxious Weed Control Board. Available: (Accessed 2004).

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