BRITISH CEREALS. 27 



absent in Barley and present in Wheat, though it requires looking 

 for. 



Let us put these distinctions in another way : 



Oats. Grain generally slender, deeply grooved, adherent 

 hairy all over or only at apex ; epiblast small and incon- 

 spicuous ,- starch grains compound. 



Rye. Grain slender, deeply grooved, compressed laterally, 

 free, hairy at apex ; epiblast absent ; starch grains simple. 



Wheat. Grain stout, deeply grooved, slightly compressed 

 laterally, free, hairy at apex ; epiblast small and incon- 

 spicuous ; starch grains simple. 



Barley. Grain stout, deeply grooved, adherent, hairy at 

 apex ; epiblast absent ; starch grains simple. 



When the grain germinates we have another means of identi- 

 fication. In Wheat and Rye the plumule will be found to emerge 

 close to the roots of the embryo ; in Barley and Oats it makes its 

 way outwards from the other end of the grain. Thus we have 

 two groups of two each ; and the members of each group are as 

 readily distinguishable, for in Wheat the roots are three in num- 

 ber, in Rye there are four ; in Oats there are three, in Barley five 

 or six. 



Putting this as plainly as possible, we have : 



Plumule emerging remote from roots of embryo. 



Roots five or six, Barley. 



Roots three, Oats. 

 Plumule emerging close to roots of embryo. 



Roots three, Wheat. 



Roots four, Rye. 



But it will be asked what is the plumule ? And in answering 

 this we will deal with a few more points to which the germination 

 of the seed in its early stage calls attention. 



The back of the grain is grooved, the groove facing the inner 

 palea when on the plant. Looking down the groove near the 

 base you will see a narrow scar ; that is the hilum, which is the 

 scar left when the grain separated from the placenta. There 



