112 



BOTANY OF CROP PLANTS 



Beyerinck has succeeded in producing crosses of einkorn 

 with dicoccum, none of which were fertile, however. Aaron- 

 sohn says that T. polonicum hybridizes with the other species, 

 T. cBstivum and T. monococcum, but the offspring are not 

 fertile. 



T. monococcum (einkorn) is a small-headed species of no economic impor- 

 tance in this country. It is cultivated to some extent in Spain, Germany, 



Fig. 38. — Spikes of the types of wheat, i, Polish wheat (Triticum polo- 

 nicum) ; 2, club wheat (T. compactum) ; 3, common bread wheat (T. aestivum) ; 

 4', Poulard wheat (T. turgidum); s. durum wheat (T. durum); 6, spelt (T. 

 spelta); 7, emmer (T. dicoccum); 8, einkorn (T. monococcum). 



and Switzerland. Grains in the ear have been found in the remains near the 

 homes of Swiss lake-dwellers of the Stone Age. It is a native of Asia Minor. 

 Triticum csgilopoides is considered to be the wild form of our cultivated ein- 

 korn. This wild species is divided into the two subspecies: T. thaoudar and 

 T. boeoticum. In the first, only the lower flower is fertile, as a rule, but both 

 bear awns, while in hoeoiicum only the lower flower is fertile and awn-bearing. 

 There is a difference of opinion as to which of these stem forms is nearest to 

 our cultivated einkorn. T. mgilopoides differs from cultivated forms of 

 einkorn in that its spikes are more fragile, and the grains smaller and lighter 

 in color. 



