Annual, monoecious (or sometimes flowers bisexual), robust herb to 2.5 m, often smaller; stems green to red; indument of stems, young leaves and inflorescence axes more or less densely pubescent with tangled white hairs or sometimes glabrous. Petiole to 3(-12) cm long; blade subelliptical, ovate, rhombic-ovate or lance-ovate, 2-10(-15) x 1-7(-10) cm, obtuse or acute, slightly notched at apex, entire or minutely crenulate. Inflorescence of large axillary and terminal spikes or panicles 1-20 cm long; bracts lanceolate or ovate, usually 3.5 mm or longer (-4.5 mm), elongated with green midvein extending into a subulate, spinulose apex, conspicuously exceeding tepals so that whole inflorescence often appears bristly. Flowers green, white or reddish. Male flowers occurring in most parts of inflorescence; tepals 5, unequal, narrowly oblong or ovate, 1.3-3.0 mm long, acute; stamens 5. Female flowers, tepals 5, unequal, oblong, longest (outer) 1.3-2.5 mm long, acute, spreading at maturity, shorter than utricle; styles (2)3. Utricle circumscissile, subglobose, 2.0-2.5 mm long, slightly to conspicuously rugulose; seed lenticular or cochleate-orbicular, 0.8-1.1 x 0.9-1.3 mm, dark reddish-brown or black, lustrous.