CHAPTER IV. 

 BRITISH CEREALS. 



]\, T O book on grasses would be complete without a few notes 

 * ^ on our cereals. None of them is included in our flora, 

 though all the best varieties are sports discovered away from 

 the fields or as individuals in an ordinary crop and undoubtedly 

 of British origin ; but being unknown to us except under cultiva- 

 tion we cannot consider them as wild. They are only four in 

 number, and owing to the large size of their flowers and fruit 

 afford us the best examples for studying the structure of the 

 Gramineae. 



Unlike grasses which rarely thrive except in company and 

 are sown broadcast, the cereals are always distinguishable by 

 the uniformity of the crop ; and with such a compact group we 

 have no difficulty in identifying them by their vegetative as 

 well as their floral characters. 



To begin with, we can recognise them by their seeds. In 

 all four the grain is grooved, but in two, Oats and Rye, it is of slender 

 build, though some Oats are coniform and some oviform. In Oats 

 the grain is adherent, whereas in Rye it is free. In both it is hairy 

 at the apex, but in Oats it is occasionally hairy all over. In 

 Rye there is no epiblast, but in Oats this is always present, 

 though not conspicuous. Finally when we make a thin section 

 for the microscope we find that in Oats the starch grains are 

 compound, while in Rye they are simple as in Wheat and Barley 

 which may be distinguished from each other as follows : First by 

 sheir shape, Wheat being slightly compressed laterally and not 

 so broad as Barley ; secondly, by the Wheat grain being free, 

 while that of Barley is adherent ; thirdly by the epiblast being 



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