Redroot Pigweed, Amaranthus retroflexus
Family: Amaranthaceae; Pigweed Family
Vegetative Characteristics:
Seedling: hypocotyl red to green, glabrous to softly pubescent; cotyledons green, pubescent
Stems: erect, 2.0 m tall, stout, usually branched, with fine short trichomes
Leaves: alternate, 2.0-15.0 cm long, 1.0-7.0 cm wide, simple, veins with trichomes on underside, long-petioled
Reproductive Characteristics:
Inflorescences: monoecious, terminal panicle of several densely crowded, stout spikes to 20.0 cm long and 1.0-5.0 cm wide; bracts 4.0-8.0 mm long, two to three times as long as sepals, very stiff; female sepals 5, 3.0-4.0 mm long, recurved, obtuse, rounded, truncate, or slightly notched at apex
Fruits: utricle, broadly ovoid or eliptical, 1.5-2.0 mm long, numerous per spike, wrinkled and rough when dry, circumscissile dehiscent
Seeds: lenticular, 1.0-1.2 mm diameter, dark red-brown
Special Identifying Characteristics:
⇒ erect, stout summer annual; spikes in thick inflorescence, more than 1.0 cm wide; stiff bracts, two or three times as long as sepals; leaves and young stems pubescent
