Mr. Woods on the Genera of European Grasses. 15 



usually embraces the base of the inner ; but in Phalaris and Achnodonton, by 

 the help of the position and direction of the lateral nerve, they have the 

 appearance of being almost valvular. The only genera in which the outer 

 glume is the largest are, Milium, Achnatherum, Gastridium and Calama- 

 grostis and Deyeuxia. The substance of the glumes is sometimes of use 

 in determining genera ; but on this head there seems to be a great dif- 

 ference in the terminology of different authors, and perhaps few authors 

 are always perfectly consistent with themselves, expressing the same cha- 

 racter by different words in different places, and even different characters 

 apparently by the same word. Thus the glumes of Milium are membranous 

 according to Kunth and Gaudin, herbaceous, if we consult Hooker. The 

 paleee of the same plant are subcoriaceous in Kunth, cartilaginous in Gaudin. 

 Kunth applies alike the term membranaceous to the paleae of Alopecurus and 

 of Phalaris, though the consistence is certainly very different. I find these 

 parts of Grasses described by different authors as carnosce, cartilaginece, co- 

 riacece, chartacece, papyracece, herbacece, membranacece, scariosce, hyalinoe, 

 tenerrime membranacece, and with different compounds of these terms. I 

 distinguish 



Filmy. Very thin and transparent. The paleae of most species of Andropo- 

 gon and Sorghum may be taken as examples of this degree of solidity. The 

 palea «,lso of Knappia, and the inner palea of the neutral floret of Oplismenus, 

 and the inner palea of some species of Agrostis and of other Grasses. 



ScARiosE. Transparent, like the preceding, but firmer: it exists in the 

 paleae of Phleum, and of many other Grasses, and in the glumes of Polypogon 

 and Stipa. 



Membranous. Still firmer ; translucent but not transparent, and often 

 coloured (but not green). We find it in the glumes of Agrostis and Arundo, 

 in the paleae of Poa nemoralis and Glycerin aquatica. 



We may use the compound term Membrano-scariose for an interme- 

 diate state, as in the glumes of Deschampsia cespitosa and of Avena pubes- 

 cens. 



Herbaceous. Green, and nearly of the texture of a leaf, as in the barren 

 floret of the Panicece. This perhaps differs more in colour than in substance 

 from membranous. 



