wheat, in botany: A genus of plants belonging to the class of triandra, and order of digynia; and in the natural system ranging under the 4th order, Graminae. The calyx is bivalve, solitary, and generally containing three florets; the corolla is bivalve, one valve being bluntish, the other acute. There are 15 species; the afflum, summer or spring wheat; hybernum, winter Lammas, or common wheat; compositum, turgidum, or cone-wheat; polonium, or Polish wheat; spelta, or felt wheat; monococcum, orone-grained wheat; prostratum, or trailing wheat-grafs; pumilum, or dwarf wheat-grafs; juncum, or rush wheat-grafs; repens, or couch-grafs; tenellum, or tender wheat-grafs; maritimum, or sea wheat-grafs; unilaterale, or spiked sea-wheat; unioloides, or linear spiked wheat-grafs.—Of what country the first five species are natives, cannot now be determined; the prostratum is a native of Siberia; the juncum, repens, unilaterale, and maritimum, are natives of Britain; the tenellum is a native of Spain; and the unioloides is a native of Italy. It may also be observed, that the first nine are annuals, the rest are perennials. See Agriculture, n° 122; and Husbandry, Part I.

Linnaeus comprehends the different kinds of wheat cultivated at present under six species; but cultivation has produced a great many varieties from these.

1. Triticum afflum, or spring-wheat, hath four flowers in a calyx, three of which mostly bear grain. The calycy stand pretty distant from each other on both sides a flat smooth receptacle. The leaves of the calyx are keel shaped, smooth, and they terminate with a short awn. The glumes of the flowers are smooth and bellying, and the outer leaf of three of the glumes in every calyx is terminated by a long awn, but the three inner ones are beardless. The grain is rather longer and thinner than the common wheats. It is supposed to be a native of some part of Tartary. The farmers call it Spring Wheat, because it will come to the fickle with the common wheat, though it be sown in February or March. The varieties of it are: Triticum afflum spica et grana rubente. Spring wheat, with a red spike and grain. Triticum afflum rubrum, spica alba. Red spring wheat, with a white spike. Triticum afflum, spica et grana alba. Spring wheat, with a white spike and grain.—2. Triticum hybernum, winter or common wheat, has also four flowers in a calyx, three of which are mostly productive. The calycy stand on each side a smooth flat receptacle, as in the former species, but they are not quite so far astern. The leaves of the calyx are bellying, and so smooth that they appear as if polished, but they have no awn. The glumes of the flowers too are smooth, and the outer ones near the top of the spike are often tipped with short awnæ. The grain is rather plumper than the former, and is the most generally sown in England; whence the name of common wheats. Its varieties are: Triticum hybernum, spica et grana rubente. Common wheat, with a red spike and grain. Triticum hybernum rubrum, spica alba. Common red wheat, with a white spike. Triticum hybernum, spica et grana alba. Common wheat, with a white spike and grain.—3. Triticum turgidum, thick spiked or cone-wheat, is easily distinguished from either of the former; for though it has four flowers in a calyx after the manner of them, yet the whole calyx and the edges of the glumes are covered with soft hairs. The calycy too stand thicker on the receptacle, which make the spike appear more turgid. Some of the outer glumes near the top of the spike are terminated by short awnæ, like those of the common wheat. The grain is shorter, plumper, and more convex on the back than either of the former species. Its varieties are numerous, and have various appellations in different countries, owing to the great affinity of several of them. Those most easily to be distinguished are: Triticum turgidum conicum album. White cone wheat. Triticum turgidum conicum rubrum. Red cone wheat. Triticum turgidum aryliflorum. Bearded cone wheat. Triticum turgidum, spica multiplica. Cone wheat, with many ears. The third variety is what the farmers call clog wheat, square wheat, and rivets. The grain of this is remarkably convex on one side, and when ripe the awns generally break in pieces and fall off. This sort is very productive, but it yields an inferior flour to what the former two species do.—4. Triticum Plo- nicum, or Polish wheat, has some resemblance to the turgi- dum,