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Willow Dells Tr - Sue Smith

Yavapai County Native & Naturalized Plants

Xanthium strumarium - rough cocklebur

Synonyms: Xanthium acerosum, Xanthium californicum, Xanthium californicum var. rotundifolium, Xanthium campestre, Xanthium canadense
Other Common Names: common cocklebur, Canada cockleburr, cocklebur, cockleburr
Plant Form: Forb or Subshrub

Family: Asteraceae

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Willow Dells Tr
Sue Smith
Willow Dells Tr
Sue Smith
Plant - summer
Willow Dells Tr
Sue Smith
Plant - summer
Willow Dells Tr
Sue Smith
Forb Plant Description

Origin: Native   Life Cycle: Annual
General Desc: Bushy annual with spiny burs that get tangled in fur and fabric.
Identification notes: Annual, moderately to much branched; leaf blades triangular or broadly ovate, green beneath; flower heads inconspicuous in sessile axillary clusters; flowers produce brownish or yellowish-brownish ellipsoid burs; found in moist, disturbed areas.
Height: To 5 feet


Habitat Description: Waste places, disturbed moist areas, fallow fields, sandy flood plains and shorelines, stream and river banks, margins of ponds and lakes; sandy and alkaline soils.
Plant Communities: Riparian, Disturbed Areas
Elevation: 1000 - 7000 feet

Flower Characteristics

Color: Greenish     Shape: Inconspicuous in round clusters     Tubular: N     Flowering Period: Jul - Oct
Description: Male flowers are tiny, in clusters at top of stem. Female flower heads are in leaf axils and form spiny, up to 1-1/2 inches long burs.

Leaf and Stem Characteristics

Leaf Color: Yellowish-green     Leaf Type: Simple     Leaf Shape: Triangular     Leaf Margin: Toothed     Leaf Attachment: Alternate     Leaves Clasp: N
Hairs: Leaves and stems     Spines: N
Leaf Description: Triangular or broadly egg-shaped to circular or kidney-shaped, 1-1/2 to 7-1/2 inches long, 1 to 6 inches wide; surfaces rough-hairy, palmately veined; margins coarsely-toothed and un-lobed or with 3 or 5 shallow lobes; tip rounded or broadly pointed.

Fruit and Seed Characteristics

Fruit Color: Brownish or yellowish-brown   
Fruit Notes: Fruits are cylindrical to barrel-shaped and hard, spiny burs; green drying to brown; burs can stick to fur and clothing and can be very difficult to extract.
Seed Notes: Burs contain 2 seeds each in their own compartment. One of the seeds in each bur may germinate the following year with the other seed taking at least 2 years to germinate.

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
Version 8.0  
Last Updated: Dec 13, 2022
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