Palmer Amaranth
Amaranthus palmeri
Leaves: Diamond-shaped and sometimes exhibiting a white or purple, V-shaped watermark (chevron) on them. Leaf petioles (especially older leaves) are as long/longer than the leaf blades.
Stems: Smooth (not hairy) and green, red, or green-red striped.
Height: Can grow very tall, up to 10 feet, especially in competition with corn.
Flowers: Produces male and female flowers on separate plants. Flowers are primarily produced on long (up to 2-3 feet, or more, in length) terminal flower heads or spikes. Male flowers will have yellow anthers with pollen. Female flowers will have sharp bracts associated with them.
Herbicide resistances in US: WSSA Groups 2, 3, 4, 5, 9, 10, 14, 15, 27.