Goathead

Goathead

A seed of the puncturevine (Tribulus terrestris). Such seeds have five burrs with two to four thorns each. The individual thorns are sharp and strong enough to puncture bicycle tires. Individual seeds always seem to lie on the ground with the thorns pointed up, and such thorns are very painful when stepped on by a bare foot. The vine is found throughout most of the U.S. Occasionally, the seed of the field sandbur is also called a goathead.