Northern Prairie Wildlife Research Center
Cocklebur (Xanthium strumarium)
- Family: Aster (Asteraceae)
- Flowering: August-October.
- Field Marks: The fruits are hairy in addition to having prickles all over them.
- Habitat: Fallow fields, along streams, in sloughs, wet prairies, disturbed soil.
- Habit: Coarse annual herb with fibrous roots.
- Stems: Erect, branched, usually hairy, up to 4 feet tall.
- Leaves: Alternate, simple, ovate, pointed at the tip, more or less heart-shaped at the base, shallowly lobed and toothed, hairy, up to 6 inches long, often nearly as broad.
- Flowers: Male and female flowers borne separately in small heads; each male head subtended by a series of small green bracts; each female head subtended by hooked prickles.
- Sepals: 0.
- Petals: 0.
- Stamens: 5.
- Pistils: Ovary inferior.
- Fruits: Achenes thick, embedded in a bur; the bur prickly, up to 1 inch long.
- Notes: Cockleburs contain a bitter poisonous substance that may cause death to grazing animals. The pollen may cause hay fever.
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