LONGSPINE SANDBUR, Cenchrus longispinus (Hack.) Fern. 1, mature plant showing burs in terminal spikes; 2, bur; 3, a single seed from a bur. Annual, reproducing by seed. Roots fibrous. Rooting may occur at the nodes of the stems when they come in contact with the soil. Stems erect, or sometimes spreading and matlike, 6 inches to 2 feet (15 to 60 cm) long. Leaves smooth, twisted, 2 to 5 inches (5 to 12.5 cm) long. Spike short, composed of spikelets enclosed in sharp spiny burs. Burs each contain 1 to 3 seeds, usually 2. Found mostly on sandy soil. Is troublesome in garden crops, lawns, and fields mainly because the spiny burs cause discomfort to persons and livestock.