common cocklebur USDA PLANTS Symbol: XAST
U.S. Nativity: Native
Habit: Forbs/Herbs
Xanthium strumarium L.

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Taxonomic Rank: Magnoliopsida: Asterales: Asteraceae
Synonym(s): cocklebur, cockleburr, rough cocklebur

Appearance
Xanthium strumarium is an annual that produces a conspicuous prickly 'cocklebur' and ranges from 0.5-6.5 ft. (0.2-2 m) in height. The relatively large, linear to oblong waxy cotyledons helps to distinguish this weed in the early stages of development.
Foliage
The first true leaves are opposite, all subsequent leaves are alternate. Leaves are triangular to ovate in outline, have stiff hairs, and are approximately 2-6 in. (5.1-15.2 cm) long. Leaves are irregularly lobed with leaf margins that have relatively inconspicuous teeth.
Flowers
Inconspicuous, greenish in color, arising from the area between the leaf petioles and the stems and at the ends of the erect stems.
Fruit
An elliptic to egg-shaped two-chambered bur, 0.5-1.5 in. (1.3-3.8 cm) long and covered with hooked prickles. Each bur contains two seeds, one that grows during the first year and one that grows a year later. Two prickles that are longer and wider than the remaining prickles project from the tip of the bur.
Ecological Threat
Xanthium strumarium is found throughout the United States and is primarily a weed of agronomic and horticultural crops, nurseries, and occasionally pastures.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Fruit(s);
Jan Samanek, Phytosanitary Administration, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Jan Samanek, Phytosanitary Administration, Bugwood.org
Additional Resolutions & Image Usage

Stem(s);
Rebekah D. Wallace, University of Georgia, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Bruce Ackley, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Seedling(s);
John D. Byrd, Mississippi State University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s); immature fruit
David J. Moorhead, University of Georgia, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
Bruce Ackley, The Ohio State University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Jan Samanek, Phytosanitary Administration, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Jan Samanek, Phytosanitary Administration, Bugwood.org
Additional Resolutions & Image Usage

Feature(s); burs
Forest and Kim Starr, Starr Environmental, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Jan Samanek, Phytosanitary Administration, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
David J. Moorhead, University of Georgia, Bugwood.org
Additional Resolutions & Image Usage

Foliage;
David J. Moorhead, University of Georgia, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); USDA NRCS. Wetland flora: Field office illustrated guide to plant species. USDA Natural Resources Conservation Service.
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
Additional Resolutions & Image Usage

Seed(s);
Jan Samanek, Phytosanitary Administration, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s); Cross-section of a bur showing the two fruit cavities, the uppermost with a seed inside.
D. Walters and C. Southwick, USDA, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s); Disseminule. Note numerous hook-tipped spines and pair of beaks.
D. Walters and C. Southwick, USDA, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.


Invasive Listing Sources: