240 A TEXT-BOOK OF GRASSES 



265. Origin of wheat. None of the cultivated wheats 

 is now found growing spontaneously, that is, as a native 

 plant. Various theories have been advanced as to their 

 origin. Some botanists have supposed them to be derived 

 from wild species now extinct or possibly existing in unex- 

 plored regions. Others have thought them to be the 

 greatly changed descendants from common wild species 

 such as Triticum ovatum Rasp. (dZgilops ovata L.). (See 

 Fabre, Journ. Roy. Agr. Soc. 15: 167. 1854.) Schulz has 

 recently suggested the probable origin of the cultivated 

 forms. He considers the cultivated wheats to be culture- 

 form groups rather than species, subspecies or races. 

 Nomenclatorially he recognizes the following: T. mono- 

 coccum, T. spelta, T. dicoccum, T. vulgare, T. compactwn, 

 T. turgidum, T. durum, T. polonicum. The first-mentioned, 

 T. monococcum, he believes is derived from the wild T. 

 cegilopoides Bal., and the third, T. dicoccum, from the wild 

 T. dicoccoides Korn., recently discovered by Aaronsohn 

 in the region of Mount Hermon, Palestine. (See Cook, 

 U. S. Dept. Agr. Bur. PI. Ind. Bull. 274. 1913. Aaronsohn, 

 Op. cit. 180: 38. 1910. Verh. Zool.-bot. Ges. Wien. 59: 485. 

 1909. Altneuland Monatschr. Wirtsch. Erschl. Palas- 

 tinas 213. 1906. Bull. Soc. Bot. France 56: 237. 1909. 

 Schweinfurth, Ber. Deutsch. Bot. Ges. 26a: 309. 1908.) 

 The second, T. spelta, he considers to have been derived 

 from an as yet undiscovered wild species. Furthermore he 

 thinks that T. vulgare and T. compactum were derived from 

 T. spelta, and that T. turgidum, T. durum and T. poloni- 

 cum were derived from T. dicoccum. (Schulz, Mitt. Natf. 

 Ges. Halle 1: 14. 1911.) Aaronsohn considers T. dicoccum 

 to be the prototype of true wheat and the former to be 

 derived from T. dicoccoides (U. S, Dept. Agr. Bur. PI, 

 Ind, Bull 180 ; 41. 1910). 



