114 POA RIGIDA. 



ribbed, the marginal ribs being broad, and having a white 

 line down the centre; intermediate ribs indistinct, dorsal rib 

 dentate on the upper portion. Inner palea somewhat shorter, 

 and having two green marginal ribs. Length from three to 

 five inches. Root annual, fibrous, and woolly. 



Flowers in the middle of July, and ripens its seed in a 

 month. 



Poa rigida is unlike all others except P. loliacea; however 

 P. rigida has the apex of upper glume on a level with the 

 base of the third floret, whilst in P. loliacea it is on a level 

 with the base of the fourth floret. 



The specimen illustrated was gathered on Colwick Park Wall, 

 by Mr. Joseph Sidebotham. 



