36 Mr. Woods on the Genera of European Grasses. 



and as long, or nearly as long as the spicula, and this contains, except in 

 Lagurus and in An-henatherum, two or more perfect florets. With the excep- 

 tion of the latter genus, the tendency of this tribe is to perfect its lower florets, 

 while the upper ones are frequently imperfect and tabescent. The palese are 

 unequal in substance, the outer being much the firmest, frequently strongly 

 ribbed, and generally with a scariose margin or extremity. The inner is alto- 

 gether scariose, except on the two keeled nerves, permanent, and embracing 

 the seed. A jointed and twisted awn rises from the back of the outer palea, 

 but this is sometimes wanting. The inflorescence is in a panicle, spreading 

 all round, except in Gaud'mia, where it is in a spike, the spiculse being in 

 opposite rows on a fragile, alternately channelled rachis. The inequality of 

 substance in the palea;, and the greater firmness of the outer, as compared to 

 the glumes, may be added to the marks already pointed out, which distinguish 

 these plants from the Arundinaceoe. They are separated from the Festucacece 

 chiefly by the nature of the awn, by the stiff" hairs at the base of the floret, 

 and by the greater comparative length of the glumes. Unfortunately, the stiffs 

 hairs at the base of the floret do not always exist ; nor is the dorsal, genicu- 

 late awn always present. The awn or seta among the Festucacece is never 

 geniculate, although it is somewhat curved and twisted in some species of 

 Bromus ; but the awn in the Avenacece arises from the substance of the palese, 

 and never from the union of several nerves as in that genus, while in the other 

 genera of Festucacece it is evidently a mere continuation of the midrib. 

 The genera are : 



1. Aira. Glumes 2-flowered, without any rudiment. Outer palea nerveless, 



included. Awn, if any, dorsal, geniculate. 



2. Deschampsia . Glumes keeled, containing (but not including) 2 perfect 



florets, and the rudiment of a third more or less developed. Awn dorsal, 

 straight. 



3. Lagurus. Glumes 1 -flowered, scariose, ending in a long fringed seta! 



Outer palea nerved, ending in two long setae and an intermediate genicu- 

 late and twisted dorsal awn. 



4. Trisetum. Glumes 2 — 6-flowered, membranous, not exceeding the florets. 



Outer palea scariose, without nerves or any distinct keel, ending in two 



