Cocklebur (Xanthium strumarium), which originates in South America, is a branched, semi-herbaceous annual plant, growing up to 1,5m high. It is an invasive weed in South Africa, where its seedlings are toxic to animals.
Adult plants have deep, sturdy taproots and the stems are reddish brown with red speckles, which makes them appear coarse. The leaves are simple, alternately arranged, egg-shaped (ovoid) to heart-shaped (cordiform), and with saw-toothed (serrate) margins.
The fruits are up to 2cm in length, brown, woody, crowned with two sturdy horns, and covered with hooked spines that cling readily to clothes and animals’ coats. There are two seeds per fruit, with one larger (about 1,5cm in length) than the other. They are blackish and ovally flattened.
DISTRIBUTION
Cocklebur is a strong competitor of annual crops and…