Canada

Powell’s amaranth (green pigweed)

Amaranthus powellii

Monoecious, erect, simple to freely-branched annual, the 1-several stems up to 2 m. tall, striate and reddish, usually glabrous below the inflorescence.
Leaves alternate, the blade lanceolate or ovate to deltoid-elliptic, 2-10 cm. long, usually glabrous, narrowed abruptly to petioles about as long.
Flowers numerous in crowded, spike-like, terminal or axillary clusters that are usually compound and up to 15 cm. long, subtended by several linear-lanceolate, spine-tipped bracts 2.5-5 mm. long; sepals somewhat unequal, those of the pistillate flowers about equal to the fruit, 2-3 mm. long, narrowly oblong, acute to obtuse; petals none; stamens usually 3; styles 3.