THE WILD WHEAT OF PALESTINE 293 



T. polonicwm, and T. sativum. Triticum sativum is a 

 collective species and contains three small species: T. 

 dicoccwm, T. spelta, and T. tenax. Triticum tenax is. 

 in turn subdivided into subspecies: T. vulgar e, T. com- 

 ■pactum, T. turgidum, and T. durum. 



This classification is essentially artificial and the dis- 

 tinctions between the groups are not always clear. Thus 

 Kornicke found it almost impossible to distinguish between 

 some forms of Triticum durum (durum wheat) and 

 Triticum dicoccum (emmer). 



Triticum monococcum holds a place distinct from the 

 other kinds of wheat because when crossed with them it 

 does not produce fertile hybrids. All the other kinds of 

 wheat can be crossed without difficulty. Moreover, a wild 

 prototype of Triticum monococcum has been known for a 

 long time and Aaronsohn found a wild form of T. mono- 

 coccum in Palestine, which is only very slightly different 

 from cultivated einkorn. All the species of cultivated 

 wheats except einkorn pass so gradually into one another 

 that it seems reasonable to suppose that they really belong 

 to one species and have had a common origin. 



Aaronsohn definitely regards Triticum hermonis which 

 he found in Palestine as the wild prototype or ancestral 

 species of all our cultivated wheats except Triticum mono- 

 coccum, the einkorn. In the following paragraphs the 

 argument which he adduces in support of his view, will be 

 quoted verbatim. 



VII. The Brittle Rachis of the Primitive Cereals 



" What," says Aaronsohn, " can we suppose the proto- 

 type of wheat to have been, and by what characters can 

 it be recognized? A fragile rachis was undoubtedly one 

 of the characters of this wild prototype.* All who have 

 » The rachis of the head of wheat is the main axial rod or stalk 



