Erect often much branched annual herb, up to 150 cm high. Stems often tinged red or pink, grey mealy hairy especially on younger parts. Leaves very variable, even on the same plant, generally rhombic-ovate to lanceolate, 1-8.5 cm long, somewhat grey-green, paler below; margin sometimes entire but mostly with up to 10 shallow teeth, the lowermost sometimes larger and lobe-like. Inflorescences large, dense heads of small rounded clusters or 'glomerules', containing minute grey-green flowers, covered in grey mealy hairs.
Lamb's quarters is a common weed across NYC and is found in disturbed areas in the Garden.