Amaranthus hybridus

Native

Cultivated fields, abandoned fields, railroads, roadsides, stream banks, riverbanks, disturbed sites.

August to October

Cream colored

12″ to 80″

This is a 12″ to 80″ tall, erect, annual forb that rises from a short, stout, often reddish taproot.

The stems are erect, stout, round in cross section, ribbed, and usually branched above the middle. They are usually green, sometimes reddish-purple, and hairless or nearly hairless below the inflorescence. They do not have spines at the nodes.

The leaves are alternate, egg-shaped, rhombic egg-shaped, or lance-shaped, 1¼″ to 6″ long, and ¾″ to 2⅜″ wide, becoming slightly smaller as they ascend the stem. They are on leaf stalks that are no more than half as long as the blade. The leaf blade is tapered or narrowed at the base and tapers to a sharply pointed tip with straight sides along the tip. The upper surface is hairless or slightly hairy along the veins. The lower surface is sparsely to moderately hairy along the veins. The margins are untoothed and flat or slightly wavy.

The inflorescence is a dense, green, branched, elongated cluster (panicle) of numerous spikes at the end of the stem, as well as smaller panicles or solitary spikes rising from the upper leaf axils. The terminal inflorescence often has numerous shorter branches at the base.

Male and female flowers are produced on the same plant. Female flowers have 5 cream colored, petal-like sepals, no petals, and 3 stigmas. Male flowers have 5 cream-colored, petal-like sepals, no petals, and usually 5, sometimes 4, stamens. Male flowers are borne at the tip of the inflorescence. The sepals are sharply pointed at the tip. Each flower is subtended by one or more bracts that are sharply pointed and shorter to twice as long as 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. The bracts subtending the fruits, together with an awn at the tip, are conspicuously longer than the fruits.

Redroot amaranth (Amaranthus retroflexus) is a more hairy plant. The sepals are rounded at the tip.