GRASSES OF BRITAIN. 205 



in length to its sheath ; — whereas in Poa pratensis the sheaths are 

 not compressed, and the upper leaf is much shorter than its sheath. 



Poa subcompressa is distinguished from Poa jiemoralis in the pani- 

 cle being much shorter and more rigid. Ligules more prominent 

 Sheaths considerably more compressed. Upper leaf not longer than 

 its sheath ; — whereas in Poa nemoralis the panicle is long and slen- 

 der, liffules very short, and the upper leaf longer than its sheath. 



This grass grows, though sparingly, in the neighbourhood of Edin- 

 burgh, on dry sandy soil and rocky places, and on the tops of old 

 walls. It has been gathered by Professor Balfoiu- in the King's 

 Park, and Mr Babington has sent me specimens gathered in ^lon- 

 mouthshire. I hare met with it growing in many places on old walls 

 near Paris, and I have also found it very common at Ais.-la-Chapelle, 

 Coblentz, Ratisbon, and Vienna. It flowers early in July, and 

 ripens its seed in the middle of August. It is a grass of not suffi- 

 cient agricultural importance to merit the attention of farmers. 



The accompan%ing figure was taken from a specimen gathered 

 near Edinburgh, 



Explanation of Plate XC. Poa subcompressa, natural size. 



Fig. 1. Part of the rachis and branches. 



2. Spikelet, showing the two glumes and seven florets. 



3. Glumes. 



4. Floret, showing the two palea, and a delicate web from the base, attach- 1 s 



ed to the glumes. 



5. Outer palea opened, showing the five ribs, three of which are hairy. 



6. Ligule of upper sheath. 



7. Oraiium, pistils, stamens, and scales. 



