ORIGIN AND RELATIONSHIPS OF RACES OF WHEAT 345 



intermediate in its ear characters between A. ovata and T. dicoccoides, 

 which Aaronsohn considered a natural hybrid, and the photographs of the 

 spikelets undoubtedly support this conclusion. 



It is highly probable that such natural hybrids are not infrequent, 

 and although the F l generation produced and grown under European 

 experimental conditions is generally sterile, the vulgar e hybrid is fertile 

 with vulgare pollen. It is also possible that the natural hybrids between 

 the wild Aegilops and the Emmer prototype the suggested parents of 

 the vulgare race are more fertile under their native climatic conditions 

 than in Central or Western Europe. 



The particular contribution made by the two species of Aegilops to 

 the vulgare race can at present only be surmised. Either of them w r ould 

 account for the keelless empty glume, but the beardless character of half 

 of these wheats has most likely come from the short-awned beardless 

 A. cylindrica. 



Many forms of T. vulgare are glaucous, others are non-glaucous and a 

 green or a yellowish-green tint ; the former agree with A. ovata, the 

 latter with its sub-species A. triaristata, which differs from the type 

 ovata chiefly in its colour, more robust growth, and the possession of 

 three instead of four awns on the empty glume. 



Empty glumes with a single long terminal awn instead of the usual 

 short apical tooth are not infrequent among vulgare and compactum 

 wheats (Figs. 165, 191), especially those from Central Asia. This 

 character I regard as evidence of the presence of Aegilops in these races, 

 for it appears in hybrids of A. ovata with T. vulgare, though neither of 

 the parents show it. The three or four long awns on the empty glume 

 of A. ovata are reduced to one in the second or third generation of the 

 cross (p. 382 and Fig. 223). 



DINKEL OR SPELT (T. Spelta, L.). That T. Spelta is in some way 

 closely related to the Bread wheats (T. vulgare) is usually admitted. The 

 characteristic arrangement and form of hairs on the young leaves, the 

 hollow culms and broad but slightly keeled empty glumes which they 

 have in common are evidences of their affinity. 



Speltoid mutations and transitional speltoid forms are not uncommonly 

 seen, more especially among the vulgare wheats coming from Central 

 Asia, Argentina, and Spain. 



T. Spelta is frequently grouped with the fragile-eared Emmers, but 

 this classification is based on imperfect knowledge of the nature of its 

 rachis. In T. dicoccoides the ear falls in pieces as it ripens (cf. Fig. 77), the 

 rachis disarticulating at the nodes, and a similar though less easy dis- 

 articulation is found in the brittle-eared forms of T. dicoccum. The 

 rachis of T. Spelta is also brittle, and when roughly treated breaks into 

 short lengths, but . the transverse fracture occurs below the point of 



