244 THE WHEAT PLANT 



which appear almost smooth, the hairs upon them measuring not more 

 than 32-64 p. long, the older leaves of such varieties being somewhat 

 scabrid. 



The auricles are usually fringed with a few long hairs. 



The ears are large, pendulous, heavy, and 



|<4/j^j^ a nearly always bearded, the sides usually 



parallel, though a few taper a little towards 

 the tip. The ears are square or oblong in 



section, the form in this respect depending 

 FIG. 151. Diagrammatic trans- 11 j . r ^\- j Di- 



verse sections of young leaves u P on the laxness or density of the ear and the 



of (a) T. turgidum and T. number and size of the grains which develop 

 pyramidale. (6) T. turgidum . , -11^ T-> ->_i i i 1 j 



(var. dinurum). * n each spikelet. Ears with closely packed 



spikelets containing four or five grains are 



almost square ; those in which the spikelets are densely packed and 

 contain only two or three grains are oblong in section and broadest across 

 the side. A few forms with lax ears and well-filled spikelets are broad 

 across, the face and narrow across the side like most of the varieties of 

 T. vulgar e. 



The ears of different forms are from 7 cm. to 11-5 cm. in length, their 

 " density " varying from 21 to over 40, the individual rachis internodes 

 measuring from 2-5 mm. to 4-66 mm. 



The number of spikelets possessed by an average ear varies from 19 1033. 



The rachis is tough, except in a few forms, which are brittle like those 

 of T. dicoccum ', it is smooth, but copiously fringed along its edges with 

 white hairs, and at the apex of each of its internodes at the base of the 

 spikelets is a tuft of similar hairs from i to 2 mm. in length. 



The spikelets are from 8 to 15 mm. broad, 10 to 13 mm. long, and about 

 4 mm. thick. They are usually 5- to y-flowered, and in some varieties many 

 of them produce three to five well-developed grains. 



The empty glumes are white, yellow, red, or dark bluish, the black 

 or dark brown pigment in the latter case being modified by a glaucous 

 covering. 



As in T. durum and other wheats, the power of forming black pigment 

 in the glumes and awns appears to be absent from some varieties ; in those 

 forms which possess it the colour is not always produced, its appearance 

 being dependent upon climatic conditions. In damp cold seasons, and 

 in very dry seasons, when the plant is prevented from developing its ears 

 fully, the colour is more or less completely kept in abeyance, but in bright 

 warm seasons it appears again, such variation occurring in plants of 

 " pedigree " lines. 



In some forms the glumes are glabrous," in others they are pubescent. 

 They are comparatively short ; those of the lateral spikelets are 8-n mm. 

 long, more inflated than those of T. durum, unsymmetrical, and 5- to 7- 



