Family: Caltrop (Zygophyllaceae)
Size: 0.5 in.
Other names: Goat's head, puncture-weed, ground bur-nut, torrito, bull-head, tackweed
Notes: Ripens to a hard star shaped nut which splits into 5 brownish gray nutlets, each having a pair of 1/4 inch long spines. Native to Mediterrean region but naturalized in the Southwest. Spines injure livestock, bare feet, bicycle tires, etc. 1 species of Tribulus in Arizona
Puncture Vine entry in the online edition of An Illustrated Guide to Arizona Weeds, Kittie F. Parker, University of Arizona Press.
Entry for puncturevine in the University of California Statewide Integrated Pest Management Project.