Xanthium strumarium L.

Asteraceae (Sunflower Family)


Cocklebur is a coarse, somewhat thick-stemmed annual growing to about 5' tall with alternate, thick and sandpapery leaves that are long-petioled, deltoid to ovate, 4" to 6" long, irregularly-toothed to lobed, green both above and below, and ± cordate at the base.  It usually inhabits sandy or grassy areas in moist or dry streambeds, next to water courses, or in other disturbed locations. Cocklebur is a monoecious species with separate staminate and pistillate flowers on the same plant, the pistillate heads being clustered below the staminate ones.  The pistillate heads are two-flowered and two-beaked, lacking a corolla, and having style branches that are exserted through the beaks.  The staminate heads are many-flowered with subglobose involucres, fused filaments, free anthers, and slender ovaries.  The bur is 3/4" to 1-1/2" long, is covered with many stout prickles, and has two incurved hooks at the end.  Cocklebur may be found throughout the California Floristic Province and in the deserts, blooming from July to October, and is a worldwide species.  Its relative, spiny cocklebur (Xanthium spinosum), in which the leaf axils are armed with three-forked spines, is less common.

Click here for Latin name derivations: 1) Xanthium 2) strumarium.
Pronunciation: ZAN-thee-um stroo-MARE-ee-um.
Click here for Botanical Term Meanings.