Culms erect, 1–4 m tall. Leaf sheaths with transverse veinlets; leaf blades 50–90 × 3–12 cm, glabrous or with tubercle-based hairs, margins scabrid, midvein stout; ligule ca. 2 mm. Female inflorescence a cylindrical "cob," with 16–30 rows of spikelets; glumes equal, veinless, margins ciliate; florets hyaline. Male inflorescence a "tassel" of many digitate racemes; spikelets 9–14 mm, unequally pedicellate, one pedicel 1–2 mm, the other 2–4 mm; glumes subequal, membranous, lower ca. 10-veined, margins ciliate, upper 7-veined; lower lemma and palea hyaline, subequal; upper lemma smaller than lower. Anthers orange, ca. 5 mm. Fl. and fr. summer–autumn. 2n = 20, 40, 80.

This plant (maize, corn) was first domesticated in Central America about 7000 years ago and is now the third most important crop in the world. The many cultivars are grown for cereal or forage, and it is also an important source of oil, syrup, and alcohol.