Plants annual. Culms (0.5)1-3(6) m tall, (0.5)1-5 cm thick. Blades
mostly 30-90 cm long, 2.5-12 cm wide. Pistillate inflorescences rames
or spikes, usually shortly pedunculate (sometimes sessile), solitary, 4-30(40)
cm long, (0.5)1-10 cm thick, with 2 or more rows of paired spikelets, hence
the spikelets 4 or more ranked, rarely terminating in an unbranched staminate
inflorescence. Caryopses concealed in fruitcases (wild taxa) or exposed
(domesticated taxon); fruitcases of wild taxa distichous, triangular
in side view; domesticated taxon without fruitcases, glumes reduced and
shallow or collapsed and embedded in the rachis. Staminate panicles 10-25+
cm, with 1-60(235) branches, internodes 1.5-8.2 mm; spikelets 9-14 mm
long, 2.5-5 mm wide; lower glumes rounded dorsally, flexible, translucent,
papery, loosely enclosing the upper glumes, the 2 lateral veins subequal to
the others, not winged. 2n = 20.
Of the five subspecies of Zea mays, only the domesticated subspecies, Z. mays subsp. mays, is widely
grown outside of research programs. Three wild subspecies are treated here,
albeit briefly, because of their importance as genetic resources for Z. mays subsp. mays.