THE MOST IMPORTANT CEREALS 165 



cently Aaron Aaronsohn of the Agricultural Experiment Station in Pales- 

 tine has discovered on Mount Hermon a wild wheat which has been 

 named Triticum hermonis by O. F. Cook of the United States Department 

 of Agriculture, who has studied in detail this interesting plant. What 

 the relationship of this wild wheat is to the diverse types of cultivated 

 wheats, it is too early to state, but this can be said, that it is doubtful 

 whether all the cultivated types of wheat arose from a single wild species 

 or from several wild species, more probably the latter is the true explana- 

 tion. The cultivated wheats may be divided into two groups, as follows : 



1. Naked wheats in which the grain comes free from the lemma and 

 palet, and the rachis is tenacious. This group includes the durum wheat 

 (r. durum), the Poulard wheat (T. turgidum), the club wheat (T. com- 

 pactum), the common bread wheat (T. cestivum) and the Polish wheat 

 (T. polonicum). 



2. Spelt wheats, in which the grain remains attached to the lemma and 

 palet and the rachis is fragile. This group includes the einkorn (T. 

 monococcum), the emmer (r. dicoccum) and the spelt (T. spelta). The 

 wheats of this group are nearest to the primitive condition, for it is gen- 

 erally agreed that the progenitor, or progenitors, of the cultivated forms 

 had a fragile rachis, and this is borne out by the fact that the wheats culti- 

 vated in ancient times had fragile rachises, such as emmer, and by the 

 fact that the wild species from Syria also agrees in this peculiarity. The 

 Triticum hermonis is the T. dicoccum dicoccoides, a wild emmer, and this 

 wild emmer is considered by Chodat to be the primitive form and he 

 concludes that wheat is indigenous to Syria. 



Description. Wheat is an annual plant with fibrous roots and usually 

 six-jointed stems, the upper or last internode being the spike-bearing one. 

 The leaf of wheat is of the usual grass type with a split sheath and thin 

 transparent ligule. The spikelets are arranged in a spike with an average 

 of 15-20 fertile spikelets in a head (Fig. 72). The number of flowers in a 

 spikelet varies from two to five, Each spikelet has two broad glumes at 

 the base. The lemmas are awned, or beardless, that is awnless. There 

 are three stamens and an ovary with two feathery styles. Two lodicules 

 are present. In northern cold, or wet climates, close pollination is the 

 rule with wheat, but in durum wheats cross pollination is habitual, and 

 this seems to be the case with primitive wheats and those grown in hot, 

 dry localities. The mature grain has a tuft of hairs, the brush, at the 

 small (stigmatic) end of the kernel, and at the opposite end is found the 



