342 THE WHEAT PLANT 



distinct from the prototypes of the Small Spelt and Emmer series, is 

 needed to account for the differentiating characters of the Bread Wheat 

 series is, however, generally recognised. 



The discovery by Fabre of peculiar plants arising from the ears of the 

 wild grass Aegilops ovata, which became gradually transformed in suc- 

 cessive generations into wheat indistinguishable from that ordinarily 

 cultivated, led him to conclude that the wheats have been derived by 

 cultivation and selection from this wild species of grass. Fabre's view 

 was shared by many eminent botanists of last century. 



In 1889 Kornicke announced that in the wild T. dicoccoides he had 

 found the prototype of his T. vulgare, which included all cultivated wheats 

 except T. monococcum. 



Solms-Laubach decided that the ancestral wild wheat is extinct and 

 only the cultivated forms descended from it exist at the present day. 



The belief that T. Spelta represents an ancestral type, and that the 

 rest of the vulgare series have been developed from it, has been somewhat 

 generally accepted, and in the phylogenetic schemes of Schulz and Flaks- 

 berger it is placed in the position of a primitive form whose wild proto- 

 type is yet undiscovered, although Schulz believes it probably exists in 

 the mountainous parts of the Euphrates-Tigris region. 



From a study of the rachis and glumes of the two plants, Stapf states 

 that he is " almost convinced " that Aegilops cylindrica, a wild species 

 indigenous in Eastern Europe and Asia Minor, is the prototype of T. 

 Spelta. 



While the characters of the wheat of the Small Spelt and Emmer series 

 can be traced with reasonable certainty to their respective prototypes, 

 from which they appear to have been derived chiefly by mutation, selection, 

 and cultivation, investigation of the morphological features of practically 

 all known forms of T. vulgare has convinced me that there is not, nor has 

 there ever been, a prototype of the Bread Wheat series. The characters 

 of T. vulgare and its allies appear to me to be those of a vast hybrid race, 

 initiated long ago by the crossing of wheats of the Emmer series with 

 species of Aegilops, and that T. Spelta is a segregate of this hybrid. 



Crossing between mutants of the same specific prototype is, I think, 

 sufficient to account for many, if not all, of the moderate number of forms 

 found among the races of the Emmer series, but the extraordinary com- 

 plexity and almost endless number of varieties and intermediate forms 

 of the vulgare race can only be satisfactorily explained by the assumption 

 of its hybrid origin from two or more distinct species. 



There is scarcely a single character, morphological or physiological, 

 which is not subject to very wide variation, and in respect of any pair of 

 its contrasting characters, such as lax and dense, bearded and beardless 

 ears, different forms of empty glume, early and late ripening period, 



