Other names: Tall waterhemp
Scientific name: Amaranthus rudis J. Sauer
Description: A warm-season annual common in row-crop fields in Southeast and Central Texas. Can be found as far south as San Patricio county. Similar to Palmer amaranth, this species is capable of producing massive quantities of seed per female plant. Glyphosate resistant populations exist across its range in Texas.
Stems: Mostly without hairs, may appear red or green (and all shades between).
Leaves: Simple, alternate, often lanceolate with petioles shorter than blade.
Inflorescence: A dioecious species (separate male and female plants). Inflorescence a terminal spike which may be simple or highly branched. Both male and female flowers subtended by bracts and without petals. Male flowers with five green sepals, female flowers without sepals. Unlike Amaranthus palmeri, female flowers soft to touch.
Seed: Glossy, dark red to black, 1 mm in diameter.