Amaranthus hybridus, commonly called green amaranth slim amaranth, smooth amaranth, smooth pigweed, or red amaranth, is a species of annual flowering plant. A. hybridus is an erect annual herbaceous plant which reproduces only by seeds. It produces a tap root and erect, often branched stems from 0.1 to 2.0 m in height. The stems are thick and often ribbed or tinged with red. Its leaves are alternate, long-stalked, and ovate to rhombic-ovate. Leaf and stem surfaces have small fine hairs.