GRASSES OF BRITAIN. XXV 



MELICA. — ^Florets inclosed within the glumes. Glumes five- 

 ribbed. Outer palea seven-ribbed. Two species, M. nutans, 3L 

 uniflora. 



CATABROSA. — Spikelets of one or two florets, much longer 

 than the glumes. Outer palea notched at the summit, three-ribbed. 

 Glumes very unequal, small, without lateral ribs. Ligules promi- 

 nent. One species, C. aquatica. 



MOLINIA. — Spikelets of one or two florets, much longer than 

 the glumes. Outer palea acute, entire at the summit, three-ribbed. 

 Glumes without lateral ribs. Ligules very small. Leaves hairy on 

 the inner surface. Two species, M. depauperata, M. ccerulea. 



AIROCHLOA. — Spikelets of two florets inclosed within the 

 glumes. Glumes equal. Outer palea three-ribbed. One species, 

 A. eristata, 



AVENA. — Glumes more than five-ribbed. Florets awned from 

 below the centre. Two species, A. strigosa^ A. fatua. 



TRISETUM. — Spikelets of three or more florets. Large glume 

 three-ribbed. Outer palea five-ribbed, with a long awn arising from 

 about the centre. Florets hairy at the base. Three species, T, 

 pratense, T. puhescens, T. fiavescence. 



ARRHENATHERUM.— Glumes very unequal. Large glume 

 three-ribbed. Outer palea seven-ribbed. Florets hairy at the base. 

 Lowermost floret awned from near the base. Uppermost floret awn- 

 ed from a little beneath the summit. One species, A. avenaceum. 



HOLCUS. — Glumes nearly of equal lengths. Large glume 

 three-ribbed. Florets inclosed within the glumes. Lowermost 

 floret with a long footstalk, about half the length of the floret. Two 

 species, H. lanatus, H. mollis. 



