346 THE WHEAT PLANT 



insertion of the spikelets and not at the exact nodal point ; indeed, dis- 

 articulation at the node is not always easy to effect, even when force is 

 used, and on this account T. Spelta should be included among the tough- 

 eared wheats. 



Exactly the same mode of fracture and at the same point of the rachis 

 is found in Aegilops cylindrica, and Stapf's conviction that these two are 

 closely related is, I think, undoubtedly correct. My view, however, 

 differs somewhat from his in that I regard A. cylindrica not as the proto- 

 type of T. Spelta but as one of its parents. 



The experiments of Fabre, Godron, and others with Aegilops x T. vulgare 

 hybrids have shown that the complete or even approximate segregation 

 of an Aegilops never occurs in any succeeding generation of their descend- 

 ants, a result almost unique and hitherto unexplained. 



T. Spelta, however, which very frequently appears among the progeny 

 of hybrids of vulgare wheats with other races, I regard as a segregate 

 nearest to the cylindrica parent. 



CLUB WHEAT (T. compactum, Host). In the chief morphological 

 characters of its young leaves, culms, glumes, and naked grain this race 

 resembles T. vulgare, and there is little doubt that both have had a 

 common origin. The great density of the ears of the race is a character- 

 istic hereditary feature, and such constant, dense, dwarf-eared forms 

 frequently arise apparently de novo among the progeny of hybrids between 

 widely different wheats with longer lax ears. I think it highly probable 

 that the compactum race arose in this way and made its appearance con- 

 temporaneously with the vulgare wheats. 



It is one of the most ancient of races, archaeological evidence showing 

 that it was widely distributed in prehistoric times, and apparently more 

 commonly cultivated at first than the larger-grained vulgare wheats. 



INDIAN DWARF WHEATS (T. sphaerococcum, mihi). Like its ally 

 T. compactum, this race probably arose as a mutant among the progeny 

 of an early hybrid. Its peculiar small round grains very closely agree 

 in form and size with Buschan's T. compactum globiforme, the naked- 

 grained wheat most commonly grown in various parts of Europe in 

 Neolithic times, and it is possible that the race now confined to India is a 

 remnant of an ancient stock. 



