Ambrosia cheiranthifolia - Gray
South Texas Ragweed
Other English Common Names: South Texas Ambrosia
Taxonomic Status: Accepted
Related ITIS Name(s): Ambrosia cheiranthifolia A. Gray (TSN 36502)
Unique Identifier: ELEMENT_GLOBAL.2.150493
Element Code: PDAST0C070
Informal Taxonomy: Plants, Vascular - Flowering Plants - Aster Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Asterales Asteraceae Ambrosia
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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: Ambrosia cheiranthifolia
Taxonomic Comments: Distinct species in large genus.
Conservation Status
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NatureServe Status

Global Status: G2
Global Status Last Reviewed: 02Mar1992
Global Status Last Changed: 02Mar1992
Rounded Global Status: G2 - Imperiled
Reasons: Only an estimated 20 population centers survive, and since most popluations are clonal, these may represent very few genetically different individual plants. The species' geographic range is limited to coastal south Texas and northeastern Mexico. Much of its original habitat has been converted to agricultural fields and pastures. The remnant, fragmented native prairies and savannahs are threatened by continued habitat distruction, agricultural chemicals, and by invasive, non-native grasses, which are commonly planted in the area.
Nation: United States
National Status: N2

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 Texas (S2)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (24Aug1994)
Comments on USESA: Ambrosia cheiranthifolia was proposed endangered on August 5, 1993 and determined endangered on August 24, 1994.
U.S. Fish & Wildlife Service Lead Region: R2 - Southwest

NatureServe Global Conservation Status Factors

Range Extent Comments: Coastal south Texas (Cameron, Kleberg, Jim Wells, Nueces Cos.) south to Tamaulipas, Mexico.

Number of Occurrences: 6 - 20
Number of Occurrences Comments: About 15-20 occurrences: 5 in S. Texas (Cameron, Kleberg, Jim Wells, Nueces Cos.) and 1 in Tamaulipas, Mexico.

Population Size Comments: Individuals difficult to count because of extensive spreading rhizomes. More than 10,000 stems at NAS Kingsville alone. Infrequent or rare.

Overall Threat Impact Comments: Threatened by continued habitat distruction, agricultural chemicals, and by invasive, non-native grasses, which are commonly planted in the area.

Short-term Trend Comments: Much of its original habitat has been converted to agricultural fields and pastures.

Other NatureServe Conservation Status Information

Distribution
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Global Range: Coastal south Texas (Cameron, Kleberg, Jim Wells, Nueces Cos.) south to Tamaulipas, Mexico.

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 TX

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
TX Cameron (48061)*, Kleberg (48273), Nueces (48355)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
12 South Corpus Christi Bay (12110202)+, San Fernando (12110204)+, Baffin Bay (12110205)+, South Laguna Madre (12110208)+*
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A silvery-green perennial herb that forms large patches of stems (1-4 dm tall) from rhizomes. Flowers (late summer-fall) are inconspicuous.
Technical Description: "Erect perennial herb, forming usually restricted often close-spaced colonies from roots; stems 1-3(-4) dm tall, grayish strigose; leaves opposite below (or nearly throughout), alternate above, oblanceolate or oblong-lanceolate, 2-4(-7) cm long; blade gradually narrowed to the sessile base, unlobed and entire-margined or the lower and larger leaves or juvenile shoots undulate-margined or shallowly pinnate, finely and densely strigose on both sides; inflorescence usually unbranched; staminate heads in racemiform arrangement; pistillate heads in small clusters in axils of leaves below "racemes;" staminate involucre saucer-shaped, about 4 mm broad, canescent, with 4 to 6 triangular-acute lobes; pales of the receptacle linear or oblanceolate, 1-nerved, ciliate toward the apex; fruiting involucres puberulent, somewhat angled, obovoid, the body about 3 mm long; beak stout, conic, 1.5 mm long; spines 4 or 5, more or less spreading, blunt, about 1 mm long." (Correll and Johnston, 1970).
Diagnostic Characteristics: Ambrosia cheiranthifolia may be characterized by median leaves of flowering stems entire and silky-pubescent (Correll and Johnston, 1970).
Duration: PERENNIAL
Terrestrial Habitat(s): Grassland/herbaceous
Habitat Comments: Grasslands and various mesquite-dominated shrublands on soils ranging from heavy clays to lighter-textured sandy loams. Most commonly found in coastal prairie communities over the Quaternary-age Beaumont Formation.
Economic Attributes Not yet assessed
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Management Summary Not yet assessed
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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: 19Jul1984
NatureServe Conservation Status Factors Author: Poole, J.M., rev. B. Carr (rev. Poole/Maybury 8/96)
Element Ecology & Life History Edition Date: 25Jun1992

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
Help
  • Correll, D.S., and M.C. Johnston. 1970. Manual of the vascular plants of Texas. Texas Research Foundation, Renner. 1881 pp.

  • Flora of North America Editorial Committee. 2006c. Flora of North America North of Mexico. Vol. 21. Magnoliophyta: Asteridae, part 8: Asteraceae, part 3. Oxford Univ. Press, New York. xxii + 616 pp.

  • 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.

  • Poole, Jackie M., W. R. Carr, D. M. Price, and J. R. Singhurst. 2007. Rare plants of Texas. Texas A&M University Press, College Station. 640 pp.

  • Turner, B.L. 1983. Status report [on Ambrosia cheiranthifolia]. Report prepared for the U.S. Fish and Wildlife Service, Albuqquerque, New Mexico.

  • U.S. Fish and Wildlife Service. 1994. Determination of endangered status for the plants Ayenia limitaris (Texas ayenia) and Ambrosia cheiranthifolia (south Texas ambrosia). Federal Register 59(163): 43648-43652.

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