50 



FIRST BOOK OF GRASSES 



Fig. 41. Spike- 



The glumes and lemma in the spikelets so 

 far examined in this lesson have been of like 

 texture, membranaceous (like a membrane or 

 skin). 

 In Muhlenbergia (Figs. 41 and 42) the lemma is 

 firmer in texture than the 

 glumes. In some species 

 of the genus the glumes 

 are much reduced, and in 

 some they are well devel- 

 oped and often awned. 

 The lemmas are promi- 

 nently 3-nerved and are 

 let of MuMen- awned or mucronate, that 



bergia foliosa. , . , , 



is, the midnerve extend- 

 ing in a minute point. 



In four of our genera the lemma at 



maturity is firm and 



hard in texture and 



the nerves are 



scarcely visible. In 



Milium (Fig. 43) the 



lemma is rigid, 



smooth, and shining 



and the palea is of 



like texture. In Ory- 



zopsis (Fig. 44) the 

 lemma bears an awn that readily disarticulates 

 at its base. The palea is nearly inclosed by the 

 lemma. 



of Milium effusum; 

 B, floret. 



Fig. 42. A, spike- 

 let of Muhlen- 

 bergia Schreberi; 

 B, branchlet 

 with the minute 

 glumes of two 

 spikelets from 

 which florets 

 have fallen. 



