[citation needed] The genus is divided into two sections: Luxuriantes, with Z. diploperennis, Z. luxurians, Z. nicaraguensis, Z. perennis; and Zea with Z. mays.

What many consider to be the most puzzling teosinte is Z. m. huehuetenangensis, which combines a morphology rather like Z. m. parviglumis with many terminal chromosome knobs and an isozyme position between the two sections.

[5] various grasses e.g. fescue, ryegrass Hordeum (barley) Triticum (wheat) Oryza (rice) Pennisetum (fountaingrasses, pearl millet) Sorghum (sorghum) Tripsacum (gamagrass) Zea mays (maize) other Zea species (teosintes) Teosintes are critical components of maize domestication, but opinions vary about which taxa were involved.

According to the most widely held evolutionary model, the crop was derived directly from Z. m. parviglumis by selection of key mutations;[6] but in some varieties up to 20% of its genetic material came from Z. m. mexicana through introgression.

Some populations of Z. m. mexicana display Vavilovian mimicry within cultivated maize fields, having evolved a maize-like form as a result of the farmers' selective weeding pressure.

"[6] Zea species are used as food plants by the larvae (caterpillars) of some Lepidopteran species including (in the Americas) the fall armyworm (Spodoptera frugiperda), the corn earworm (Helicoverpa zea), and the stem borers Diatraea and Chilo; in the Old World, it is attacked by the double-striped pug, the cutworms heart and club and heart and dart, Hypercompe indecisa, the rustic shoulder-knot, the setaceous Hebrew character and turnip moths, and the European corn borer (Ostrinia nubilalis), among many others.

Virtually all populations of teosintes are either threatened or endangered: Z. diploperennis exists in an area of only a few square miles; Z. nicaraguensis survives as about 6000 plants in an area of 200 × 150 m. The Mexican and Nicaraguan governments have taken action in recent years to protect wild teosinte populations, using both in situ and ex situ conservation methods.