Puncturevine is annual, prostrate or somewhat ascending, mat forming, with trailing stems, each ½ to 5 feet long. Leaves opposite, hairy, divided into 4 to 8 pairs of leaflets, each about ¼ to ½ inch long and oval. Flowers are yellow, 1/3 to ½ inch wide with 5 petals, borne in the leaf axils. Fruits consist of 5 sections which, at maturity, break into tack-like structures with sharp, sometimes curving spines, each section 2-to4-seeded.
Puncturevine was introduced from southern Europe and is now widely scattered over much of the U.S. It grows in pastures, cultivated fields, waste areas, and along highways and roads. The hard, spiny burs damage wool, are undesirable in hay, and may be injurious to livestock. Bicycle tires are frequently punctured by the burs. The seed will remain dormant in the soil for 4 to 5 years, which makes eradication difficult. Because of its sharp burs, puncturevine has been spread over a wide area by animals and vehicles. Flowering and seed production occur from July to October.
Non-standard names: goathead, Mexican sandbur, Texas sandbur.
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