RIVET OR CONE WHEAT 243 



each straw, as well as with the great length of their stems and leaves, and 

 consequent abundance of green assimilating tissue. Moreover, the 

 number of spikelets possessed by each ear is usually greater among the 

 varieties of T. turgidum than among the varieties of T. vulgar e. 



To ensure the greatest success with these wheats in England they 

 should be sown not later than the middle of October on warm, well-drained 

 soils ; when sown in spring they ripen very late, and the grain at harvest 

 is often poorly filled. 



A few varieties possess flinty grains, but the majority of Rivet wheats 

 have a soft, opaque, starchy endosperm, from which is obtained " weak " 

 flour, suited to the requirements of the biscuit-maker, but of less value to 

 the baker on account of the poor physical quality and reduced amount 

 of its gluten. The dough is somewhat greyish and " short " ; loaves of 

 bread made from Rivet flour are more or less dense and non-porous in 

 texture, and of small volume when compared with loaves made from the 

 same weight of dough prepared from the " strong " flour of certain 

 varieties of T. vulgar e. 



The bran is thick and abundant. 



Rivet wheats are chiefly utilised by the miller for mixing with the strong 

 Canadian and Russian wheats. 



GENERAL CHARACTERS OF T. turgidum, L. 



T. turgidum is the tallest of the wheats ; its straw, which is somewhat 

 slender but strong, with a dull striate surface, averages about 150 cm. 

 (69 inches), the length in different varieties measuring from 120 to 180 cm. 

 (48 to 72 inches) or more ; the upper internode is curved and in many 

 cases solid or filled with pith ; even in those varieties with all the internodes 

 hollow the wall of the straw is often thick and pithy and the central 

 cavity comparatively small. I have found none with walls as thin as 

 those of T. vulgar e. 



Well-developed culms of many kinds possess six or seven internodes 

 above ground ; the average lengths of the successive internodes from 

 below upwards were found in a few common varieties to measure 5, 10-5, 

 14-5, 19, 29, and 60 cm. respectively. 



In some varieties the young shoots have the prostrate " winter " habit ; 

 others have the semi-erect or erect " spring " habit. 



The leaves of the young plants are short, narrow, and usually dark 

 bluish-green, those of the culm long and broad. 



In almost all varieties both sides are invested with soft white hairs 

 from 1 20 to 250 p long, as in T. dicoccum, the leaves to the touch resembling 

 velvet and appearing clothed with a silvery covering when viewed along 

 the surface (Fig. 151). Some forms of var. dinurum have young leaves 



