Poaceae (Grass family)
Group: Monocot (Grass)
Annual clump-forming grass, which roots at the lower nodes, and has a spike of spiny burs, native to the American tropics. It is commonly found on sandy soils in disturbed sites but can also be found in cultivated fields and pastures.
Seedling leaves are hairless with a hairy ligule, and fine hairs on the margin. Seedling leaves are folded in a bud, the blade is rough like sandpaper with a smooth sheath that is compressed and often reddish.
Leaves of mature plants are smooth with compressed or flattened sheaths, hairy on the margins, and 1-1/2 to 10 inches long and 1/4 to 3/4-inch wide. Ligule is a fringe of hairs.
Stem is round, erect to trailing, 10 to 35 inches long from an abruptly bent base, often reddish at nodes.
Flower or seed head is a cylindrical raceme with spiny burs. Spiny bur has one whorl of united flattened spines with one to several whorls of shorter bristles below. Spine tips turn purple with age.
Roots are fibrous.
Propagation is by seed.