00 lianmnitji hi Cereals 



(a) Tr. iHOiiococcunt L. is iiiiaiiiuiously separated by gunetists as 

 an independent species fniiii all tlie other seven, principally on acconnt 

 of the sterility of its hybrids with the other seven species of wheat, 

 which has been proved by many investigators [Vilniorin, Beijerinck, 

 Koernicke, Tscherniak](18), whereas all these latter (2V. vid<jare, com- 

 pactum, dicoccttm, tmr/iduni, durum, pulonicain, and Spelta) in crossing 

 give more or less fertile hybrids'. The wild progenitors of onr cnltivated 

 varieties of Tr. monococcum have been known for a very long time, 

 whereas the wild prototypes of other species were found only a few 

 years ago. 



The genetic individualisation of Tr. monococciuu is confirmed too by 

 its fungal reactions. All its known wild and cidtivated varieties are 

 perfectly inniiune to brown and yellow lusts, and in this respect occupy 

 a separate jjlace among other species of wheat. In literature we find 

 also indications that they are equally immune to stinking smut, TiUetia 

 tritici{6). 



(b) Tr. compactum Host. — dwarf wheats, according to modern views 

 are so nearly allied to common wheats, Tr. vidgare Vill., that many 

 authors unite them into one species. As we see in the table given 

 above, their fungal reactions on mildew and brown rust are the same. 



(c) Tr. puloiiicvm L. and Tr. turgiduin L. by systematists and 

 genetists (Koernicke, Schulz, Beijerinck and others) are considered as 

 species nearly allied to Tr. durum Desf. " Bei einzelnen Formen"(of 

 Tr. turgiduin) — says Schulz — " kann man zweifeln, ob man sie zu Tr. 

 turgiduin oder Tr. duruiu zurechnen soil" (10, p. 150). " Tr. polonicuin" 

 — says Beijerinck — " ist ohne Zweifel nur eine halbmonstrose Abart von 

 Tr. durum " (3). " Es giebt unter Tr. durum " — says F. Koernicke — 

 " Sorten, deren Korner in der Liinge, Glasigkeit und der hellen Farbe 

 genau denen von Tr. polonicum gleichen " (8, p. 897). These three 

 species are alike not onl}' in the structure of their ears, but also in their 

 vegetative organs. 



The characteristics of these species in their fungal reactions to 

 P. triticiua, P. glumaruiii and Erysrphe graminis are identical. 



(d) Tr. dicoccuiii, Schr. — Emmer — according to the current view, 

 is a polymoi'phic progenitor species from which the su.sceptible and 



' Oulj quite recently M. Blaringhem reported in C. R. ile I'Acad. ties Scienc, 1914, 

 T. 1-58, No. 5, that he suceeedetl in obtaining a few fertile livbrids ? Tr. monococcum L. 

 var. vulgure Kcke. x J Tr. iliiriim var. Macaroni, as a result of many crossings of these 

 species. Many of his other crossings of Tr. mDnornmim with different species, proved to 

 be unsuccessful or sterile. 



