GRASSES OF BRITAIN. 239 



one-fourth of its length beyond the summit of the outer palea ; foot- 

 stalk of the second floret less than one-fourth the length of the floret ; 

 — whereas in Aira ccespitosa the ligule of upper sheath is long and 

 acute, twice as long as broad ; aicn not extending more than one- 

 eighth its length beyond the summit of the outer palea, very often much 

 less ; footstalk of the second floret about half the length of the floret. 



Airaflexuosa is distinguished from Aira caryophyllea in the ligule 

 of upper sheath being obtuse, and about as long as broad ; outer 

 palea jagged at the summit, not beaked ; sheaths of leaves rough only 

 when felt from above downwards ; — whereas in Aira caryophyllea the 

 ligule of upper sheath is acute, and long, nearly twice as long as 

 broad ; ow^er palea somewhat beaked at the summit; sAra^As of leaves 

 rough only when felt from below upwards ; the spikelets not half the size. 



Airaflexuosa is distinguished from Aira prcscox in being a much 

 larger plant with a spreading panicle ; ligule obtuse, and about as 

 long as broad ; sheath of leaves rough only w^hen felt from above 

 downwards ; aicn extending about one-fourth of its length beyond 

 the summit of the outer palea ; — whereas in Aira pracox the panicle 

 is contracted, close ; ligule long and acute, about twice as long as 

 broad ; sheaths of leaves rough only when felt from below upwards ; 

 axon extending half its length beyond the summit of the palea. 



The accompanying figure was taken from a specimen gathered in 

 the neighbourhood of Edinburgh. 



Explanation of Plate CVII. Airaflexuosa, natural size. 



Fig. 1. Spikelet, showing the glumes and two florefs. ^ . 



2. The two florets removed from the glumes, showing the awns and inner | ^ 



palea. I "B. 



3. Ligule almost always cloven. | 3 



4. Pistils, stamens, and scales. J 



I pre\-iously noticed this plant among the grasses of Scotland, but 

 the figure and description there given were not sufficiently minute to 

 distinguish it from some of the more closely allied species. I scarcely 

 think this plant to be the Airaflexuosa of Smith, since in the English 

 Flora it is stated that the awn arises from the middle of the outer 

 valve, and is txvice as long as the glumes. For further description 

 see pages 55 and 5Q. 



