CHAPTER III. 



KEY FOR THE IDENTIFICATION OF COMMON GRASSES. 



Grasses are scientifically distinguished chiefly by their 

 flowers. However, since the flowers are present for only 

 a month or so in each year, the following key has been 

 constructed to assist in the identification of the common 

 grasses by their roots, stems, and leaves alone, and the 

 recognition of grasses by their flowers has been left to the 

 figures scattered through the preceding pages. In the case 

 of annual grasses, however, the flower characters are used 

 for identification, since the flower can nearly always be 

 found either exposed or wrapped in the sheath. To use the 

 following key it is necessary first to have complete specimens, 

 including a good portion of the root, and next it is necessary 

 to make careful observations, not on a single leaf but on 

 several, before deciding that any particular structure is 

 absent. 



Under each of the figures on the left hand of the page 

 in the following scheme will be found two alternatives. 

 Within one or other of these alternatives every grass must 

 faU. When close examination has determined within which 

 of the alternatives the specimen under study is included, 

 follow that line out to the right hand side of the page, 

 where there wiU be found either the name of the grass, or 

 the figure under which (when appearing on the left of the 

 page) the investigation must be pursued. For instance 

 take Cocksfoot. It has no hairs, no rhizome, no colouration 

 at the base, but it has a strongly compressed sheath. Now 

 turn to the key. Under figure 1 on the left Cocksfoot 

 faUs within the second alternative, hairless — and so we 

 run out to figure 14 on the right of the page. Now find 14 



