Tribulus terrestris
Tribulus terrestris is an annual plant in the caltrop family (Zygophyllaceae) widely distributed around the world. It is adapted to grow in dry climate locations in which few other plants can survive. It is native to warm temperate and tropical regions in southern Eurasia, Africa, North America, and Australia. An aggressive and hardy invasive species, T. terrestris is widely known as a nuisance for its small woody fruit – the bur – having sharp spines which attach to crop workers, pedestrians, bicycle tires, and the mouths and fur of grazing animals.