172 THE WHEAT PLANT 



The leaves of young plants in winter forms lie spread out on the surface 

 of the soil, in spring forms they are more erect ; the blades are narrow, 

 from 4 to 10 mm. across, bluish-green at first, yellowish-green later, and 

 covered with very short hairs, 50-80 ^ long, on both surfaces. 



Tillering is extensive, particularly so in the slow-growing winter forms. 



The straw, which, according to variety, reaches a height of 60-120 cm. 

 (2-4 feet), is smooth and thin, but tough and elastic, usually hollow in all 

 the internodes except the basal one, which in some kinds is solid : the 

 walls of the straw are thin. 



On each there are four or five nodes, the upper ones being clothed with 

 somewhat conspicuous deflexed hairs, those next the ground often destitute 

 of hairs or nearly so. Just below each node the straw in the common 

 forms is a brownish-purple colour. 



In straws with four internodes the average successive lengths of the 

 latter from below upwards were found to measure 6, n-6, 22, and 42 cm. 

 respectively, straws with five internodes measuring 4, 12-6, 16, 25-5, 

 and 42-7 cm. 



The combined sheath and blade of the fully developed leaves on the 

 straws are from 25-5 to 35-5 cm. (10-14 inches) long, -6--J cm. broad, 

 the hairs on them being fewer and longer than on the young leaves of 

 autumn and spring ; the overlapping edge of the sheath is generally 

 fringed with soft hairs. 



The ligule is short and truncate, with irregular teeth ; a pair of small 

 auricles with accompanying long hairs are present at the base of the 

 blade. 



The ears are bearded, erect, laterally flattened and thin, superficially 

 resembling those of two-rowed barley. They vary in length from 4-5 

 to 9 cm., having a width of 7 to 10 mm. across the two-ranked side and 

 3-5 mm. across the narrow face of the ear. 



The spikelets are packed closely in an imbricate manner, small ears 

 having 22-25 spikelets, the largest 45 or more ; the density (D) = 50-55. 



The rachis is flattened (1-2-1-5 mm. wide and -3~-4 mm. thick) and 

 very brittle, breaking into pieces 1-5 mm. long, to the upper end of which 

 is attached a single spikelet. In all forms the rachis is smooth, but 

 in some the edges are fringed with straight white hairs, especially at 

 the point of insertion of the empty glumes, and a tuft of similar hairs is 

 present on the rachis in front of the base of each spikelet between the 

 glumes. 



The spikelets generally possess three flowers, the upper one of which 

 is always imperfect and sterile ; in some varieties only the lower flower 

 is fertile, while in other kinds the first and second flowers of the spikelets 

 produce ripe grains. The terminal spikelet of the ear is very minute and 

 barren. 



