10 THE BLADE. 



the side opposite the blade, though exceptional cases are cited 

 where the sheaths are closed, as in Bromus (chess), Melica 

 (melic grass), and some others. The sheaths of the upper leaves 

 of most grasses are split down to the node, but those of the lower 

 leaves in very many species are closed. In some cases the sheaths 

 are closed at an early stage of development, but later they are 

 split open part of the way down by the enlargement of the grow- 

 ing culm and the young leaves as they push upwards. This is 

 illustrated in Fig. 7. 



sheaths closed. 1 x id. (Sudworth.) 



At the upper end of the sheath there is often a membranous 

 scale, tongue, or fringe, called the ligule. The reader will con- 

 sult Fig. 51, and observe the ligule of a leaf of June grass. That 

 part of the leaf, which spreads away from the culm, is known 

 as the 



Blade or lamina,, and is usually sessile and slender, tapering to a 

 point. 



To the ordinary observer the blades of grasses seem to be very 

 nearly alike. Even Linnaeus thought so, but to the botanist of 

 to-day they present very marked differences. 



The abortive leaves on root-stocks, generally consist mainly of 

 rudimentary sheaths. Commonly,, all the leaves on a stem are 

 much alike, but in some cases the lower leaves are quite unlike 

 those above. The lower leaves of some species of Bambusa 

 (bamboo), Oryzopsis asperifolia (mountain rice), Panicum 



