The Origin of Wheat. 169 



The various kinds of grasses differ very little from 

 one another in general plan ; the flower in almost all 

 is constructed strictly on the lines above mentioned ; 

 and the leaves i.i almost all are just the same soft 

 pensile blades, making them into the proper green 

 sward for open, unwoodcd, wind-swept plains. But 

 like almost all other very dominant families, they 

 have split up into an immense number of kinds, dis- 

 tinguished from one another by minute differences in 

 the arrangement of the florets and the spikelets ; and 

 these kinds have again subdivided into more and more 

 minutely different genera and species. One great 

 group, with panicles of a loose character, and very 

 degraded spikelets, has given origin to many southern 

 grasses, from some of which the cultivated millets are 

 derived. Another great group, with usually more 

 spiky inflorescence, has given origin to most of our 

 northern grasses, from some of which the common 

 cereals are derived. This second group has again split 

 up into several others, of which the important one 

 for our present purpose is that of the Hordcineac, or 

 barley-worts. From one of the numerous genera into 

 which the primitive Hordeineae have once more ^plit 

 up, our cultivated barleys take their rise ; from another, 

 which here demands further attention, we get our 

 cultivated wheats. 



