344 



THE WHEAT PLANT 



of the lateral spikelet is oblong, broad and truncate at the apex, with a 

 short terminal awn of variable length, and a much shorter lateral tooth, 

 that of the terminal spikelet bearing one or two very long awns. The 

 flowering glumes are awnless or only shortly bearded. 



FIG. 214. Empty glumes and spikelets of 

 (i) Aegilops cylindrica and (2) T. Spelta, 

 illustrating mode of fracture of the rachis 

 (xa). 



It is conceivable that the heterogeneous race 

 of T. vulgare wheats with its numerous Aegilops 

 characters may have arisen from the hybridisa- 

 tion of these two species, or from one, or 

 both, by mutation, selection, and cultivation, 

 but I think this is much less possible than 

 the view I have just expressed. The greater 

 length of ear, frequently keeled empty glume, 

 larger grain, and occasional solid culm appear to me to need the intro- 

 duction of another species like that of T. dicoccoides and its derivatives. 



Both species of Aegilops mentioned have been artificially hybridised 

 with Emmers or with T. vulgare. Cook also refers to a Syrian specimen. 





FIG. 213. Ear of Aegilops 

 cylindrica, with two empty 

 glumes (nat. size). 



