i8o THE WHEAT PLANT 



The plants tiller freely and the first few straws expand to full length 

 a week or ten days before the rest, which are much shorter and remain 

 green some time after the first ears are ripe. At the time of harvest each 

 plant exhibits ears dead ripe with the terminal spikelets shed, others just 

 ripe, some green, as well as a few still enclosed in their leaf-sheaths. 



The culms are slender but strong, from 65 to 100 cm. long (about 26-40 

 inches), with 4 or 5 internodes above ground, the upper one often reaching 

 a length of 50-60 cm. (about 20-30 inches). In some varieties they are 

 hollow throughout, in others the upper internode is solid or nearly so. 



Before the ears escape from the upper leaf-sheaths the shoots with 

 the culms enclosed lie close to the surface of the soil, but towards the 

 middle of May at Reading the shoots rise rapidly, becoming more or 

 less vertical in about a week ; later they incline again, the ripe ears often 

 touching the ground. 



The bases of the culms of mature plants curve away from each other 

 in a characteristic decumbent manner, the plants appearing to occupy a 

 considerable area of ground. 



The ears are bearded, stiff, and laterally compressed, measuring 4 to 6 

 mm. across the face of the spikelets, and 7 to 9 mm. across the two- 

 ranked side of the ear. They vary in length from 8 to 10 cm. without the 

 awns and consist of 12 to 17 spikelets ; D = 17-20. 



The surface of the flattened rachis is smooth and shining, but along 

 its edge is a conspicuous fringe of white, yellow, or dark-brown hairs which 

 are often 5 mm. long, and visible when the ear is viewed from the side ; 

 in front of the base of each spikelet is a tuft of similar hairs which some- 

 times extend across the rachis from one margin to the other at that 

 point. 



The lateral spikelets usually have three flowers, the first only, or first 

 and second of which are fertile ; they are from 15 to 20 mm. long, 5 to 6 mm. 

 broad, and 3-5 mm. thick. 



The terminal spikelet is usually, though not always, sterile, and its 

 glumes are generally well developed. 



The lateral empty glumes, which may be yellowish or pinkish white, 

 red, uniformly black, striped along the margins or spotted irregularly with 

 dark brown, are from 10 to 15 mm. long, the outer half 2-4 to 3 mm. across, 

 the inner half about i mm. broad. They are coriaceous and rigid, usually 

 5-7 nerved, long and narrow, with a scabrid keel and either glabrous 

 or covered with silky hair. The apical tooth varies much in length and 

 form ; in some cases it is bluntish, in others acute and 1-5 mm. long ; 

 it is usually straight but may curve slightly inwards or outwards (Fig. 119). 



The strongest nerve on the broad exposed half of the glume converges 

 towards the base of the apical tooth, where it ends in a secondary tooth 

 which in some specimens is -5 mm. long, in others very short. 



