The millets are a group of small-seeded species of cereal crops or grains, widely grown around the world for food and fodder. They do not form a taxonomic group, but rather a functional or agronomic one. Their essential similarities are that they are small-seeded grasses grown in difficult production environments such as those at risk of drought. They have been in cultivation in East Asia for the last 10,000 years. The millets include species in several genera, mostly in the subfamily Panicoideae, of the grass family Poaceae. Of the major and minor millets (not including those plants sometimes called millet) all of the species are in the tribe Paniceae of the subfamily Panicoideae except for finger millet. The most widely-cultivated species in order of worldwide production are.: Pearl millet (Pennisetum glaucum) Foxtail millet (Setaria italica) Proso millet also known as common millet, broom corn millet, hog millet or white millet (Panicum miliaceum) Finger millet (Eleusine coracana) Minor millets include: Barnyard millet (Echinochloa spp.) Kodo millet (Paspalum scrobiculatum) Little millet (Panicum sumatrense) Japanese millet (Echinochloa esculenta) Guinea millet (Brachiaria deflexa = Urochloa deflexa) Browntop millet (Urochloa ramosa = Brachiaria ramosa = Panicum ramosum) Teff (Eragrostis tef) and fonio (Digitaria exilis) are also often called millets, as more rarely are sorghum (Sorghum spp.) and Job's Tears (Coix lacrima-jobi).