114 BOTANY OF CROP PLANTS 



T. compaclum (club wheat) varieties are said to be adapted to tlie 

 Pacific Coast and Rocky Mountain States. In club wheats, the spikes 

 are only two or three times as long as broad, and typically broader 

 at the top than at the base, thus appearing somewhat club-shaped. 'I"lu' 

 joints of the rachis are very short, so that the spikelets are crowded and often 

 stand outright. J 



T. (Bslivum (common wheat). — The bread wheats of the world are large!)- 

 varieties of ccslivum. 



Origin of Wheat. — A few years ago, Aaronsohn brought 

 from Syria a wild emmer which was named by Koernicke 

 Trilicum dicoccum dicoccoides {T. licrmonis Cook) (P'ig. 

 40). Later, in an expedition in Upper Galilee to the north 

 of Lake Tiberias, he found this wild emmer again, and, on 

 Mount Hermon near the village of Arny, he found it very 

 common and in a variety of forms. This was at an altitude 

 of 1,500 to 2,000 meters. Chodat concludes that wheat is 

 indigenous to Syria. He considers that T. dicoccum dicoc- 

 coides, a form with a fragile rachis, is the primitive type 

 of wheat. It is interesting to note that the grains of this 

 "wild wheat" are not inferior in weight or size to those of 

 the best cultivated varieties. 



It is well agreed that the prototype of our cultivated 

 wheats, whatever it is, is one with a fragile rachis. The rigid 

 rachis is considered to be developed by man. It is known 

 that the wheats cultivated in most ancient times were those 

 with fragile rachises, such as emmer. Furthermore, all 

 genera and species related to wheat, such as Aegilops and 

 Agropyron, etc., have a fragile rachis. The only cultivated 

 wheats of today with brittle rachises are einkorn, emmer, 

 and spelt. 



It is observed that cross-pollination is more prevalent in 

 Aaronsohn's primitive wheat than in cultivated forms. This 

 may be due to the fact that it grows in a warm, dry climate, 

 while most cultivated wheats belong to northern cHmates, 



