45 



and, either separately or combined, are frequent 

 accompaniments of this characteristic form of leaf 

 blade. Soils which are dry or liable to drought, such 

 as sands or windy hillsides, are the natural habitats of 

 these species. Some hardy plants can adapt them- 

 selves to conditions of extreme dryness by adopting 

 the bristle form of blade ; such are crested dogstail 

 and smooth-stalked meadow grass. In Poa maritima 

 the bristle-like (concave) blades serve partly as water 

 stores, and are, accordingly, soft and succulent. 



Group IX. Hard-bladed Grasses. Page 58. 



Hard grasses are either bristle or broad bladed ; the 

 former belong to Group VIII., the latter are alone 

 included here. Poor and dry soils, or those liable to 

 drought, are the natural habitats of these grasses. 



The blade is rarely flat, usually concave, or rolled 

 up. The apex is excessively hard and sharp a thorn 

 to all intents and purposes. The surface is often 

 covered with wax (glaucous), which gives a peculiar 

 colour to the foliage. 



Group X. Hairy Grasses (including those species 



in which the ligule is a tuft of hair}. Page 59. 

 Hair, like hardness (Group IX.) and diminution of 

 leaf surface (Group VIII.), is associated with grasses 

 adapted for growth on dry and poor land. As moisture 

 and richness of soil increase, the hair becomes- 

 diminished or short, and, at times, disappears ; thus it 

 happens that hairy and hairless varieties of the same 

 species may be found. The sheath part of the leaf 



