COAMON WHEAT, T. vulgare, cestivum, or satipunt, grows to a height generally of 3 or 4 ft., and has ears or spikes generally 3 or 4 in. long; the spike 4-cornered, the spikelets about 4-flowered; the pales' ventricose, ovate, truncate, mucronate or awned, com pressed under the point, rounded at the back, the grain free. In consequence of long cultivation, in a great variety of climates, the cultivated varieties of wheat arc very numerous, more so than in any other kind of grain. New varieties are continually coining into notice; and many are in high estimation in particular districts, although little known beyond them. some botanists have attempted to distinguish species among them, appropriating the name adivant to the awnless kinds, and 7. hybernum to the awned; but intermediate forms are very numerous, and the length or shortness of the awn seems to depend upon accidental circumstances. Nor do the awnless or beardless kinds perfectly correspond with the summer wheat cf farmers, preferred for sowing in spring with a view to a crop in the same season, and the awned or bearded kinds to the winter wheat, sown in autumn, as some of the hardy varieties of winter wheat are awn less, and some of those usually sown in spring are bearded. Besides being classified as bearded and beardless, the varieties in cultivation are also distinguished according to the color of the grain, as white and red wheats. Some having the ears covered with a short soft down are known as woolly wheats. There are also differences in the length and compactness of the spike, and in the size and form of the grain, which is more rounded in some, and more elongated in others. A number of varieties, having the spike very compact or square, have been sometimes classed together under the name of 1. co mpactum, and the distinction is very obvious and permanent, although there is no reason for regarding it as characterizing a distinct species. Akin to this is the Mummv WHEAT (7'. compositam), in which the spike is branched, and which is said, but on in sufficient evidence, to have been produced from seeds found in mummy-cases in Egypt. Mummy wheat has been grown in England, of which the ears have had 10 or 11 branches, and 150 grains have been found in one ear; while 60 cars have been pro duced by a single seed. Notwithstanding these apparent advantages, however, this variety does not serve the purposes of the farmer so well as some others. In another group of varieties with compact ears (T turgidum of some botanists), the glumes are remarkably tumid, and always awned. These are known by the names of gray wheat, Pollard wheat, duckbill wheat, etc., and in Germany are commonly called English PoIonian wheat (T.Polonicum) is the common name of a number of kinds of a very peculiar appearance, with a long, loose, and somewhat nodding spike; the glumes awned, and remarkably long—twice the length of the florets. The stems also very tall, sometimes more titan 6 ft. These kinds, sometimes called Greemn or 310G.A. DORE WHEAT, are cultivated in some parts of the s. of Europe, in the S. of Siberia, and in Africa. HARD WiimaT, or Honsv WHEAT (7'. durum), has rather small, elongated, and very hard grains, the palew have remarkably long awns, and the leaves are very broad. It ismueh cultivated in the countries near the Mediterranean, and Dr. Boyle sug gests that it would be a valuable acquisition to India, as it yields a good crop on com paratively sterile soils.
The red varieties of wheat are generally more hardy than .the white; the grain is inferior in quality, and yields less flour, bnt these disadvantages are more than counter balanced in many soils and situations by the greater productiveness of the crop. Red wheats are therefore preferred for comparatively poor soils, but the white kinds arc gen orally cultivated wherever the soil and climate are suitable. The varieties with long straw yield the best crops in dry seasons, but the short-strawed kinds are best when the season is wet. Wheat is particularly suited to clay soils, and rich heavy learns; but. with good farming, excellent crops are produced even on light sandy or gravelly, and on elial:y soils. Where the climate is most, a light dry soil is most suitable; soft deep soils. being productive chiefly of straw. The land intended for wheat must, at least in Brit ain, be in a high state of cultivation. Wheat is commonly sown after green crops,
isans, or bare fallow; in the s of England, often after grass or clover. It may be sown, I least in autumn or the beginning of winter, when the ground is so saturated with mei-ture, that any other kind of grain would be almost sure to perish. It is either sown In adezist or in drills, and the practice of drilling becomes more and more prevalent, 1 eth on account of the saving of seed and the superiority of the crops produced. The land prepared for wheat is very often manured with farm-yard manure; artificial manures —as guano—are also used. In Scotland, it is a common practice, when wheat is to be grown after turnips, to plow down the in autumn before the wheat is sown, and to apply guano in spring. Nitrate of soda is another favorite top-dressing for wheat, but sometimes causes the plants to grow too rapidly, so that they become tender, and suffer from climatic influences. Many farmers use both guano and nitrate of soda for top-dressing wheat, and the nitrate of soda is often mixed with common salt, which is thought to be useful in giving strength and vigor to the wheat plants, preventing i lodging and mildew. Wheat ought to be reaped before it is dead ripe, unless when it is intended for seed, and IL ought to be stacked as soon as it is sufficiently dry to be free from danger of heating. On very rich land wheat sometimes becomes too luxuriant in spring, and its growth needs to be repressed by cutting the leaves with a scythe—a prac tice essentially agreeing with that mentioned by Virgil in his Georgics (i. 111), of allow ing cattle to feed upon the young blades: Quid, qui, ne gravidis procumbat cutmus aristis, Luxunem segetum terlera depascit in herbil, Quum prirrim sulcos tequant rata? The relative proportions of straw and grain differ very much in different varieties of wheat. and according to differences of soil, climate, and season. The proportion of the w eight of grain to that of the whole plant when dried so as to be ready for stacking, larks from 20 to 47 per cent. The composition of the grain itself varies considerably, cc to the proportions of starch, gluten, etc., which it contains. One hundred parts of the train of wheat, dried in the ordinary manner, contain on an average—water, 14.83 gluten, 19.64; albumen, 0.95; starch, 45.99; gum, 1.52; sugar, 1.50; oil, 0.87; vegetable Lher. 12.34; ash, 2.36; total, 100.00.
The ash is rich in phosphoric acid, magnesia, and potash. Its composition is as fol lows: Potash, 29.97; soda, 3.90; magnesia, 12.30; lime, 3.40; phosphoric acid, 46.00: sulphuric acid, 0.33; silica, 3.35; peroxide of iron, 0.79; chloride of sodium, 0.09; total, 100.00. For the processes by which starch and gluten are obtained from wheat, see these articles.
The value of wheat depends mainly on the quantity of fine flour which it yields, the best wheat yielding 76 to 80 per cent, sometimes even 86 per cent, of fine flour, whereat; inferior kinds seldom yield more than 68 per cent, and sometimes only 54 to 56 per cent. in general, the smoother and thinner the grain is in skin, the greater is the produce of fine flour. The greater part of the husk of wheat is separated from the flour by the miller, and is known as bran. That portion of the bran which is more finely divided than the rest receives the name of sharps or pollard. See the articles BRAN and Fisoun.
Wheat-straw contains, on an average, in its ordinary state of dryness--nitrogenous substances, 1.85; non-nitrogenous substances, 67.50; mineral substances, 4.59; water, 26.00; total. 100.00; and the composition of the ash is as follows: Potash, 12.14; soda, 0 60; magnesia. 2.74; lime, 6.23; phosphoric acid, 5.43; sulphuric acid, 3.88; silica, 67.88; peroxide of iron, 0.74; chloride of sodium, 0.22; total 100.00.
The principal diseases to which wheat is subject, some of which are often produc Live of great loss to the farmer, are either owing to or connected with the presence of parasitic fungi. See BUNT, MILDEW, RUST, and SMUT. An animalcule causes the dis ease known as ear-cockles (q.v.). Wheat suffers also from the ravages of numerous species of insects.—Sec HEsswe FLY,WIIEAT-FLT, CORN-MOTH, and IN IREWORM. The larva of a ground beetle (zabras gibbus) is often very destructive to young wheat in winter and spring.