Mr. Woods on t/ie Genera of European Grasses. 37 



acute teeth, with an iuterinediate slendei' g-eniculate and twisted dorsal 

 awn. Seed without a furrow and without a crest. 



5. Avena. Glumes nearly equal, 2 or more flowered, herbaceous, with a sca- 



riose margin. Outer palea scariose, nerved, ending in two points, with 

 an intermediate geaiculate and twisted dorsal awn. Seed furrowed, and 

 hairy or crested, elliptic-oblong, attached to the inner palea. 



6. Gaudhiia. Spiculœ many-flowered, in two o])posite rows on an alternately 



channelled brittle rachis. Glumes very unequal, the longest (superior) 

 much shorter than the spicuia. 



7. Arrhenatherum. Glumes 2-flowered, tlie lower barren, with a geniculate 



and twisted dorsal awn. Awn of the fertile floret short and straight. 

 Palete scariose, the outer ribbed and ending in two points. 



8. Holcus. Glumes 2-flowered, the lower perfect, awnless ; the upper barren or 



perfect, with a dorsal awn. Paleœ witliout ribs, hardening on the seed. 



9. Dantlton'ia. Glumes 2 — 3-flowered, membranous, as long as the spicuia. 



Outer palea quite smooth and coriaceous below, rounded at the back, 

 bifid, witli a firm, broad, intermediate point, which sometimes becomes 

 the base of a geniculate awn. 



The difference of habit seems to justify the separation oi Deschampsia from 

 A'lra. It has usually the more or less perfect indication of a third floret, which 

 is wanting in the latter genus. The straight awn also rising froui near the base 

 is never wanting, and such an awn is found in no species of Aira. I am moi'e 

 inclined to rest upon this character than upon the 4 teeth of the paleœ, which, 

 it seems to me, are not cut wàth such precision as to give much confidence in 

 their always occurring in the same number ; and similar teeth are not unfre- 

 quent in Airajlexaosa. Indeed I find hardly any Grass where this part has 

 the firmness and regularity exhibited in the figures of Palisot de Beauvois. I 

 unite Cori/nephoras and Airopsis to the remaining species of Aira. The first 

 has a distinct and beautiful character in its clubbed awn and the little tuft of 

 hairs at the genicula, but the habit is that of some species of Aira. Airop.si.s 

 has been separated on its want of an awn, and on the three lobes or teeth 

 which terminate the inner palea. Yet Kunth says, "obsolete triloba," which 

 does not indicate a clear distinction. What he considers as genuine species 



