294 ESSAYS ON WHEAT 



studied the question agree as to this. All agronomists 

 and all botanists regard a rigid rachis as an acquired 

 characteristic, developed by man under cultivation and 

 having a tendency to destroy the plant's natural capacity 

 for dissemination. 



" All of the genera and species related to wheat, as 

 Aegilops, Agropyron, etc., have the fragile rachis, a neces- 

 sity in order that the grain be assured a wide dissemina- 

 tion. It is also needful that the grain remain fixed in 

 its glumes as a general protection against premature 

 germination, decay and destruction by enemies. But this 

 characteristic, so useful to the plant itself, was a draw- 

 back to its use by man. Wheat vsdth a brittle rachis re- 

 quires to be harvested before complete maturity and is 

 difficult to handle. Moreover, grains that are held too 

 closely in the glumes can not be thrashed with flails, 

 but a special system of mills must be used. In Egyptian 

 tombs 6,000 years old have been found heaps of emmer 

 hulls, a careful inspection of which clearly indicates that 

 they were thrashed by such mills, so that their use must 

 date from the most ancient times. 



" Wild wheat, the same as -wild oats and wild barley, 

 must have been provided with the means for ready dis- 

 semination. Man, however, naturally wished to develop 

 forms which are not so difficult for him to handle, and 

 along this line he has succeeded in obtaining a rigid rachis 



which bears the spikeleta. Bordeum juhatum, the Wild Barley, 

 Squirrel-tail Grass or Skunk-tail Grass of the prairies, has such a 

 brittle rachis. As soon as the head is ripe, the rachis breaks up 

 into some twenty or more joints to each one of which are attached 

 three little spikelets, the center one containing a single grain. 

 Every one knows what a successful weed Wild Barley is. It is its 

 brittle rachis, however, which makes its dissemination possible. 

 Were its rachis to become rigid, as in our cultivated wheats and bar- 

 leys, the scattering of its grains would be prevented and no doubt it 

 would quickly cease to be noxious. A. H. E. B. 



