74 



History of Wheat. 



tivated rye and barley the spindles are tough, and in rye and certain 

 kinds of barley, the naked barleys, the grains are loose in the husks 

 and separate easily, while in the other barleys the grains together 

 with their special husks (flowering glume and pale) are loose in the 

 spikelets. But although they are loose they are not loose enough 

 to fall out very readily or without the application of mechanical 

 pressure, such as is applied in threshing. This enormously 

 facilitates reaping, and, where the grains are loose, their subse- 

 quent separation from the husks ; it determines to a great extent 

 the economic value of these cereals, while the same conditions 

 would naturally be disadvantageous or even fatal to plants in their 

 natural states. And what is true of the cultivated and the wild 

 ryes and barleys is mutatis mutandis true of cultivated and wild 

 rice and of the cultivated and wild millets. If we now apply the 

 same reasoning- to the wheats of the tenax group — that is, the 

 wheats with tough spindles — this character, with its correlations, 

 loses practically all its value as a guide for taxonomic purposes, 

 and we are thrown back, after eliminating it, on what is left of 

 structural differences or resemblances. It is true a great deal has 

 been said about the sexual affinities of the wheats, and the long 

 series of experiments by the Vilmorins, Beyerinck, Rimpau, and 

 others have thrown a flood of light on the facilities of the wheats for 

 hybridisation. Much has been made especially of the difficulty of 

 crossing Einkorn with other wheats, and its position as a distinct 

 species has on that account been universally admitted. But common 

 wheats have been successfully crossed with, structurally, much 

 more remote species of Mgilops and even with rye. Moreover, 

 so-called generic hybrids are becoming more and more frequently 

 known, while, on the other hand, many species structurally very 

 similar resist all attempts at crossing. Therefore the argument 

 from sexual affinity to genetic affinity loses very much of its force; 

 in fact, the latter and its degrees will always have to be inferred 

 in the first place from structural resemblances, the term " struc- 

 tural " including external as well as anatomical characters. I will 

 now set out briefly the genetic relations of the wheats as they 

 appear to me viewed from that basis, and I will start from the 

 two wild wheats, Triticum cegilopioides and Triticum. dicoccoides. 



Triticum cegilopioides (Balansa) is a species ranging from the 

 Balkan Peninsula and the Crimea to Syria and Upper Meso- 

 potamia. Koernicke distinguishes two races, a weaker one from 

 the Balkan Peninsula and a more robust one from the Asiatic part 

 of the area. The structural resemblance of this species and the 

 Einkorn, Triticum monococcum, is so complete that it is quite 

 evident and generally admitted that the Einkorn has originated 

 from Triticum cegilopioides. It has given rise to few races, and 

 such as there are point rather to the Asiatic variety than to the 



