|Photo by John R. Gwaltney Southeastern Flora.com|
|Division:||Magnoliophyta - Flowering plants|
|Class:||Magnoliopsida – Dicotyledons|
|Family:||Asteraceae ⁄ Compositae|
| Ambrosia artemisiifolia|
|Natural range of Ambrosia artemisiifolia from USDA NRCS Plants Database.|
Common name: Common ragweed
Synonyms: A. artemisiifolia Linnaeus var. elatior (Linnaeus) Descourtils; A. artemisiifolia Linnaeus var. paniculata (Michaux) Blank; A. artemisiifolia Linnaeus var. artemisiifolia; A. elatior Linnaeus; A. monophylla (Walter) Rydberg; A. glandulosa Scheele
Annual. Are rhizomatous, perennial herb with pubescent stems and usually freely branched. The leaves are opposite, the upper are alternate, linear, 1-4.5cm long, 0.5-3mm wide, entire, the base are attenuate, and pubescent on both surfaces. The petioles are obscured by decurrent blade tissues. The racemes are 3-20cm long. The involucres are 1.5-3mm long. The nutlets are black in color, are pubescent at the apex, obovoid in shape, turgid, and 1.6-2.1mm long. Flowers September to October.
Annual. Grows 0.2-2m tall, with a taproot. Has freely branched stems. The leaves are deeply bipinnately dissected with acute sinuses, the lower are opposite, the upper are alternate, 5-15cm long. The segments are mostly less than 1cm wide and are acute. The pistillate involucres are fascicled in upper leaf axils, obovoid in shape, pubescent to glabrate, 2.5-3.5mm long, 1.5-2.5mm in diameter, angulate, each with 5-6 rarely fewer, erect projections toward the apex. The staminate heads are 2-4mm broad, irregularly more or less 5-lobed, peduncles 1-6mm long. The nutlets are brown in color and 3-3.5mm long. Flowers August to frost.
It is common throughout Florida. and throughout the entire United States. It has been found in open pine woods, mixed hardwoods, wet hammocks, and along dried up shores of ponds. It does well in a number of disturbed areas including old fields, drainage ditches, pastures, roadsides, sandy vacant lots, railroad gravel, blackland prairie soil, camping areas, wet pastures, levees, drainage ditches, along edges of mixed forests, recently disturbed boggy areas, along canals, and agricultural fields. It thrives in dry sandy soils to wet, peaty soils in high intensity light in open areas.
Associated species include Agalinis divaricata, pine, hickory; Euphorbia, Andropogon, Bidens, Paspalum urvillei, P. notatum, Eragrostis oxylepis, Eleusine indica, Digitaria sanguinalis, Cyperus surinamensis, Ambrosia artemisifolia, Strophostyles helvola, Solanum americanum, S. sisymbriifolium, Daubentonia drummondii, Sesbania exaltata, cabbage palmetto, Emilia fosbergii, Paspalum setaceum, Heterotheca subaxillaris, Boerhavia diffusa, Bothriochloa ischaemum; Croton capitatus and various grasses.
Seed bank and germination
It has a persistent seedbanks that can remain in the soil even after years of disturbance. Seeds require an after-ripening period before germination occurs; germination occurs after near freezing temperatures.
It can live where winter-burned annually and has been found in firelanes of annually-burned pinelands.
Use by animals
The following caterpillars eat the foliage, flowers and seeds: Schinia rivulosa (Ragweed flower moth), Synchlora aerata (Wavy lined emerald), Tarachidia erastrioides (small bird dropping moth), and Tarachidia candefacta (olive shaded bird dropping moth).
Seeds are also eaten by the thirteen line ground squirrel, meadow vole, and prairie vole.
Diseases and parasites
The pathogenic fungus Albugo tragopogi (white rust fungus) attacks ragweed and decreases pollen production. It is used as a control agent to limit the amount of ragweed allergens.
Conservation and management
Ragweed is a common allergen. The pathogenic fungus Albugo tragopogi (white rust fungus) can be used as a control agent to limit the amount of ragweed pollen produced.
Cultivation and restoration
References and notes
- Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 1016-1018. Print.
- Wunderlin, Richard P. and Bruce F. Hansen. Guide to the Vascular Plants of Florida. Second edition. 2003. University Press of Florida: Gainesville/Tallahassee/Tampa/Boca Raton/Pensacola/Orlando/Miami/Jacksonville/Ft. Myers. 296. Print.
- Hall, David W. Illustrated Plants of Florida and the Coastal Plain: based on the collections of Leland and Lucy Baltzell. 1993. A Maupin House Book. Gainesville. 74. Print.
- Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: Loran C. Anderson, Tom Barnes, R. Barbezat, Sarah Beem, S. Bennett, Kurt E. Blum, Michael B. Brooks, R. C. Darby, Frank DiCecco, William B. Fox, Mary A. Garland, Robert K. Godfrey, Bruce Hansen, G. G. Hedgcock, Norlan C. Henderson, Brenda Herrig, C. Jackson, T. Kanno, Robert Kral, Gary R. Knight, Elmo Law, Martha Lee, S. W. Leonard, S. J. Lombardo, C. L. Lundell, Travis MacClendon, Karen MacClendon, Sidney McDaniel, Richard S. Mitchell, J. B. Morrill, John B. Nelson, R. A. Norris, H. Okazaki, Dan Pittillo, A. E. Radford, Lloyd H. Shinners, Cecil R. Slaughter, Bill Stangler, William R. Stimson, Amanda R. Travis, Charles S. Wallis, Keenan Windler, and Wendy Zomlefer. States and Counties: Alabama: Baldwin. Colorado: Jefferson. Florida: Brevard, Columbia, Dade, Escambia, Franklin, Indian River, Jackson, Jefferson, Leon, Liberty, Okaloosa, Pasco, Polk, Putnam, and Wakulla. Georgia: Colquitt, Decatur, Fulton, Grady, and Thomas. Illinois: Coles, Cook, and Lawrence. Iowa: Fremont. Louisiana: Ouachita. Kansas: Riley. Maryland: Baltimore. Mississippi: Harrison and Oktibbeha. Missouri: Cass, Greene, and Ray. North Carolina: Ashe, Chowan, Macon, Madison, and Wayne. Oklahoma: Ottawa. Pennsylvania: Huntingdon. South Carolina: Dorchester, Lexington, and Richland. Tennessee: Grundy and Polk. Texas: Dallas. Virginia: Giles, Montgomery, and Van Zandt. Other countries: Japan.
- Nelson, G. PanFlora: Plant data for the eastern United States with emphasis on the Southeastern Coastal Plains, Florida, and the Florida Panhandle. www.gilnelson.com/PanFlora/ Accessed: 7 DEC 2016
- []Illinois Wildflowers. Accessed: March 29, 2016
- Kirkman, L. Katherine. Unpublished database of seed dispersal mode of plants found in Coastal Plain longleaf pine-grasslands of the Jones Ecological Research Center, Georgia.
- Rothrock, P. E., E. R. Squiers, et al. (1993). "Heterogeneity and Size of a Persistent Seedbank of Ambrosia artemisiifolia L. and Setaria faberi Herrm." Bulletin of the Torrey Botanical Club 120(4): 417-422.
- Bazzaz, F. A. (1970). "Secondary Dormancy in the Seeds of the Common Ragweed Ambrosia artemisiifolia." Bulletin of the Torrey Botanical Club 97(5): 302-305.
- Hartmann, H. and A. K. Watson (1980). "Damage to Common Ragweed (Ambrosia artemisiifolia) Caused by the White Rust Fungus (Albugo tragopogi)." Weed Science 28(6): 632-635.