Cereals
2 of the 7 encyclopedias on this shelf carry an entry for Cereals. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a term derived from Ceres, the goddess of corn. Beans, peas, and lentils are sometimes included among the cereals, but, properly speaking, the term is confined to the flour- and meal-producing seeds of plants belonging to the grass family. The eight prominent cereals of North America are Indian corn or maize, wheat, rye, oats, barley, buckwheat, rice, and Kaffir corn. They furnish the larger part of human food. Speltz and millet may be added to the list. Buckwheat is not a grass, but is included usually because of its use as buckwheat flour. The following tables are arranged from the last United States Census Report: Grain. Acres. Bushels per Acre. Barley 4,470,196 26.8 Buckwheat 807,060 13.9 Corn 94,916,911 28.1 Kaffir corn 266,513 19.4 Oats 29,539,698 31.9 Rice 351,344 13.5 Rye 2,054,292 12.4 Wheat 52,588,574 12.5 All cereals 184,994,588 Bushels. Value. Barley 119,634,877 $41,631,762 Buckwheat 11,233,515 5,747,853 Corn 2,666,440,279 828,258,326 Kaffir corn 5,169,113 1,367,040 Oats 943,389,375 217,098,584 Rice 4,728,710 7,891,613 Rye 25,568,625 12,290,540 Wheat 658,534,252 369,945,320 All cereals 4,434,698,746 $1,484,231,038 See Agriculture Ceres, se'rez, in Roman mythology, the goddess of grain and harvest, whence the term, cereal. No special myth seems to have been attached to her worship until the fifth century, when the Romans identified with her the Greek Demeter, introducing from Sicily the rites of worship performed in honor of the Greek goddess. They also adopted the Greek myths connected with Demeter, especially that of Persephone, the Roman Proserpine. See Demeter
Collier's New Encyclopedia (1921)
a term derived from Ceres, the goddess of corn; though sometimes extended to leguminous plants, as beans, lentils, etc., is more usually and properly confined to the Gramineæ, as wheat, barley, rye, oats, and other grasses, cultivated for the sake of their seed as food.