100 FIELD CROP PRODUCTION 



by roaming tribes in their journeys across the country. 

 Recently, however, a wild wheat has been found growing 

 in the eastern Mediterranean countries which is thought 

 by some to be an ancestral or closely related form, from 

 which, or from a common ancestor of which, our present 

 day wheat has developed. The wheat plant is so old 

 that it is a most difficult task to determine its ancient 

 family record. It is believed by De Candolle to have had 

 its origin in the Valley of the Tigris and the Euphrates, 

 and from there to have spread at first into China and 

 Egypt, and later to have been carried, with the spread 

 of civilization, into all temperate parts of the world. 

 So far as is knowoi, it was not grown in America until 

 after the discovery of this continent by Columbus. 



83. Botanical characters. — Wheat is an annual belong- 

 ing to the tribe Hordse of the grass family. The prom- 

 inent characters that distinguish the species of this tribe 

 are the one to many flowered spikelets which are sessile, 

 and arranged alternately upon the rachis, forming a spike. 

 Rye, barley, and rice are closely related to wheat. Wheat 

 belongs to the genus Triticum, of which it is the only 

 prominent species, and is characterized by one spikelet 

 at each joint of the rachis, the outer glumes of which 

 terminate in a beak. The flowering glume may have 

 either short or long awns, or may be awnless. Wheat 

 may be either a fall or a spring annual, some varieties 

 being adapted to fall and others to spring seeding. When 

 the seeding is done in the fall, it is called winter wheat ; 

 when seeded in the spring, it is called spring wheat. 



84. The roots. — The roots of the wheat plant, like 

 those of the corn, may be divided into temporary and 

 permanent systems. When a kernel of wheat starts to 

 grow, it sends out a whorl of three roots, which form the 



