CHAPTER II. 



THE VEGETATIVE ORGANS (continued). 



The leaves of all our grasses consist of the blade, 

 which passes directly into the sheath, without any petiole 

 or leaf-stalk (Fig. 1). 



The sheath is usually obviously split, and so rolled 

 round the intemode that one edge overlaps the other, 

 but in the following grasses the sheath is either quite 

 entire, or ouly slit a short way down, the two edges being 

 fused as it were for the greater part of its length. 



Sheath more or less entire. 



Glyceria aquatica and G. fluitans. 



Melica mniflora and M. nutans. 



Dactylis glomerata. 



Poa trivialis (Fig. 8), P. pratensis, P. alpina. 



Sesleria cosridea. 



Bromus (all the species). 



Briza media and .B. minor. 



In some cases — e.g. Arrhenatherum, Bromus asper, and 

 Holcus lanatus — the sheath is marked with a more or less 

 w. 2 



