PREFACE 



THE vast importance of the Natural Order Graminacese is 

 partly due to the large number and world-wide distribution 

 of its species, but more especially to the great economic value 

 which many of these plants possess. Apart from numerous 

 varieties some 3,600 species have been described, of which rather 

 more than 100 are natives of the British Isles. 



The enormous importance of our cereal grasses is apparent to 

 everyone, but apart altogether from these, our native grasses are 

 worthy of our highest attention, if only on account of the large 

 proportion of agricultural land occupied by them. Of the total 

 area of forty-seven million acres under grass and other crops in 

 the United Kingdom, some twenty-seven million acres are now 

 (1917) under permanent grass. Of the remaining area about six 

 and a half million acres are occupied by Rotation Grasses and 

 Clovers. 



This is a time when we are all hopeful that the area under 

 permanent grass will speedily be reduced. However, it is obvious 

 that in proportion as we extend the area under arable cultivation, 

 we should specialise upon and 'improve as much as possible our 

 remaining grass land, in order that it may carry a correspondingly 

 larger number of live stock. 



A great proportion of the existing grass land is far from being 

 of the best quality possible. Much of it is weed-covered in the 

 sense that such plants as Buttercups, Daisies, Plantains, Hawk- 

 weeds, etc. — to say nothing of the inferior grasses — occupy the 

 ground upon which our better forage plants would thrive. At 

 a very moderate estimate twenty per cent, of the total area is 

 weed-covered in the above sense, which means that an area 

 equal to at least 5,000,000 acres is covered with comparatively 

 worthless herbage. 



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