– Description:
– Cockleburs are coarse, herbaceous annual plants growing to 50–120cm tall.
– Leaves are spirally arranged with deeply toothed margins.
– Some species, notably Xanthium spinosum, are very thorny with long, slender spines at the leaf bases.
– Flower heads are of two types, one producing only pollen and the other producing seed.
– Cocklebur seeds are produced in hard, spiny, globose or oval double-chambered burs that stick to fur and clothing for seed dispersal.
– Biology:
– Cockleburs are short-day plants, initiating flowering when days are getting shorter in late summer and fall.
– Flowering typically occurs from July to October in the Northern Hemisphere.
– They can also flower in the tropics where daylength is constant.
– Specific citation needed for additional information.
– Diversity:
– Over 200 names have been proposed for species, subspecies, and varieties within the genus Xanthium.
– Most proposed names are synonyms of highly variable species.
– The Global Compositae Checklist recognizes various accepted species of Xanthium.
– Some species include Xanthium albinum, Xanthium argenteum, Xanthium catharticum, Xanthium cavanillesii, and Xanthium inaequilaterum.
– Xanthium saccharosum and Xanthium spinosum are widespread species nearly cosmopolitan.
– Legal status:
– Cocklebur is listed as a noxious weed in Arkansas and Iowa in the United States.
– Specific citation needed for further details.
– Toxicity and uses:
– The common cocklebur is native to North America and has become an invasive species globally.
– It invades agricultural lands and can be poisonous to livestock such as horses, cattle, and sheep.
– Seedlings and seeds are the most toxic parts of the plant.
– Cocklebur has been used for making yellow dye due to its edible seed oil.
– In traditional Chinese medicine, Xanthium strumarium is known as cang er zi and is used to treat nasal and sinus congestion.