Wildflowers of Toronto's High Park​​

​Xanthium strumarium

​Family: Composite

Blooms: July to October
Habitat: Open areas with moist sandy soil. 

Height: Up to 1.5 m
​Flowers: Very tiny greenish.

Male flowers, consisting of a few disk florets, grow at the branch tip and wither after releasing pollen into the air.

Female flowers, having 2 spiny bracts, grow in clusters at leaf axils.

​​Fruit: A woody green oval bur with hooked spines which cling to clothing or animal fur for dispersal. It contains 2 seeds. One germinates quickly; the other may survive for decades before germinating.