Amaranthus retroflexus

Native

Common

Cultivated fields, pastures, yards, fencerows, roadside ditches, disturbed sites.

July to September

Green to yellow

8″ to 60″

This is a 8″ to 60″ tall, erect, annual forb that rises from a shallow, fleshy, often reddish taproot.

The stems are erect, stout, light green, reddish near the base, and usually branched above the middle. They are densely to moderately covered with short, soft hairs. They do not have spines at the nodes.

The leaves are alternate, egg-shaped to diamond-shaped, ¾″ to 6″ long, and ⅜″ to 2¾″ wide. They are on leaf stalks that are half as long to as long as the blade. The leaf blades are tapered or narrowed at the base. They usually taper to a point at the tip with straight sides along the tip. Sometimes there is a small notch at the tip with a short, sharp, abrupt point in the notch. The upper surface is hairless or slightly hairy. The lower surface is hairy along the veins. The margins are untoothed and flat or slightly wavy.

The inflorescence is a 2″ to 8″ long, dense, green, branched, elongated cluster (panicle) of numerous spikes at the end of the stem and branches, as well as smaller panicles or solitary spikes rising from the upper leaf axils.

Male and female flowers are produced on the same plant. Female flowers have 5 white, petal-like sepals, no petals, and 3 stigmas. Male flowers have 5 white, petal-like sepals, no petals, and 4 or 5 stamens. The sepals are rounded at the tip. Each flower is subtended by one or more bracts that are sharply pointed and longer than the sepals. The pointed bracts give the inflorescence as bristly appearance.

The fruit is an egg-shaped to elliptic, 1 ⁄16″ to ⅛″ long, membranous bladder (utricle) with a single seed.

Green amaranth (Amaranthus hybridus) is a mostly hairless plant. The sepals are sharply pointed at the tip.