common cocklebur

Xanthium strumarium L.

Description from Invasive.org

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.

Resources

Selected Images from Invasive.org

View 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
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Seedling(s)
John D. Byrd, Mississippi State University, Bugwood.org
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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 NRCS PLANTS Database , USDA NRCS PLANTS Database, Bugwood.org
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Seed(s)
Jan Samanek, Phytosanitary Administration, Bugwood.org
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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
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Fruit(s) Disseminule. Note numerous hook-tipped spines and pair of beaks.
D. Walters and C. Southwick, USDA, Bugwood.org
Additional Resolutions & Image Usage

Distribution