Amaranthus hybridus smooth pigweed Amaranthaceae AMHY*; Bx, br, sf, pb (DeCandido 2001), wv (Yost et al. 1991); NY, bl (Stalter and Tang 2002), hb; Q, a; K, p; R, hs, lc, sm, wp;


Amaranthus hybridus. Peter Greenwood (Accessed 3/2014).

Amaranthus hybridus. © Peter Greenwood (Accessed 3/2014).

Amaranthus hybridus is an annual C4 herb (Costea and Tardif 2003), to 2 m tall, from a reddish taproot; stems branching, finely wooly-hairy above, often pinkish or red (especially if stressed), generally smoother and darker than A. retroflexus

Leaves alternate, stalk elongate, egg-shaped to rhombic, 5-15 cm long, tip blunt to acute, pale green to purplish below. 

Flowers dull green to reddish, male and female separate in same inflorescence, (no petals) sepals 5, 0.1-0.2 cm about equal to fruit, tip pointed, surrounded by bracts 0.3-0.4 cm, sharp-tipped, longer than flower, densely crowded; inflorescence of bristly spikes often nodding at tip. 

Fruit dry, papery, slightly puckered,1-seeded, opening by a suture around the middle; seeds dark, shiny lens-shaped, 0.1 cm. Seeds dispersed by wind, birds and mammals as well as farm machinery in rural areas. (Costea et al. 2004

Wetland status: UPL. 

Frequency in NYC: Occasional. 

Origin: Tropical America. 

Habitat: Weed of open areas, on bare soil, fill. 

Notes: Used a a vegetable in Tropical America and Africa. Ground seeds used in cereals in North America. Plants preyed upon by a number of nematodes and fungi and numerous insects (Costea et al. 2004).