50 



FIRST BOOK OF GRASSES 



The gliunes 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- 

 FiG. 41. Spike- nently 3-nerved and are 

 let ofMuhien- awued 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 

 MUium (Fig. 43) the 

 lemma is rigid, 

 smooth, and shining 

 ., , ^ and the palea is of 



— . -_. -., spikelet -^ 



of MUium effumm; 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. 



Fig. ^. A, spike- 

 let of Muhlen- 

 bergia Schreberi; 

 B, branohlet 

 with the minute 

 glumes of two 

 spikelets from 

 which florets 

 have fallen. 



