WILD PROTOTYPES OF WHEAT AND OTHER CEREALS. 39 



One of these, Tri Hewn tenax, is in turn subdivided into subspecies: 

 Triticum ralgare (wheat). [Triticum aestivum.] 

 Tri tic it in compact ii m (short-eared wheat, club wheat). 

 Triticum turgid urn (Poulard wheat). 

 Triticum durum (durum wheat). 



This classification is essentially artificial, and the distinctions 

 between the groups are very difficult to maintain. Near the close of 

 Kornicke's life, after having made a specialty of this study for forty 

 years, he declared that it was almost impossible to distinguish between 

 some forms of Triticum durum (subspecies of T. tenax) and Triticum 

 dicoccum (small species of the collective species sativum). 



The behavior of crosses and hybrids also indicates a very close 

 relationship among the so-called species. Thus, Vilmorin crossed 

 Triticum aestivum and T. durum and obtained a T. spelta. Triticum 

 polonlcum occupies a somewhat unique place on account of its long 

 glumes, but it hybridizes with the other species and is regarded itself 

 as only a hybrid. Triticum monococcum alone holds a place entirely 

 distinct from all of the others because of its refusal to hybridize 

 with the rest. In fact, all of the other species pass so gradually into 

 one another that it seems more than probable that all of the wheats 

 belong to one species. 



THE BRITTLE RACHIS OF THE PRIMITIVE CEREALS. 



What can wo suppose the prototype of wheat to have been, and by 

 what characters can it be recognized? A fragile rachis was undoubt- 

 edly one of the characters of this wild prototype. All who have 

 studied the question agree as to this. All agronomists and all bot- 

 anists regard a rigid rachis as an acquired characteristic, developed 

 by man under cultivation and having a tendency to destroy the 

 plant's natural capacity for dissemination. 



All of the genera and species related to wheat, as Aegilops, Agropy- 

 ron, etc., have this fragile rachis, a necessity in order that the grain 

 be assured a wide dissemination. It is also needful that the grain 

 remain fixed in its glumes as a general protection against premature 

 germination, decay, and destruction by enemies. But this character- 

 istic, so useful to the plant itself, was a drawback to its use by man. 

 Wheat with a brittle rachis requires to be harvested before complete 

 maturity and is difficult to handle. Moreover, grains that are held 

 too closely in the glumes can not be thrashed with flails, but a special 

 system of mills must be used. In Egyptian tombs 6,000 years old 

 have been found heaps of emmer hulls, a careful inspection of which 

 clearly indicates that they were thrashed by such mills, so that their 

 use must date from the most ancient times. 



Wild wheat, the same as wild oats and wild barley, must have been 

 provided with the means for ready dissemination. Man, however, 



180 



