GRASSES OF SCOTLAND. 8l 



ribbed ; Jirst joint about half-way up the stem : — whereas in Poa 

 polynoda the Jiorets are perfectly free ; outer palea five-ribbed : se- 

 cond Joi?it about half-way up the stem, and the first joint near the pa- 

 nicle. (Plate XXXIX. ) 



From Foa pratensis, in the upper leaf bemg about equal in length 

 to its sheath ; stem very much compressed, and contracted under the 

 panicle : outer palea only three-ribbed ; — whereas in P. pratensis the 

 upper leaf is much shorter than its sheath : stem very seldom com- 

 pressed; outer palea five-ribbed. (Plate XXXI.) 



From Poa nemoralis, in the ligule of upper sheath being prominent : 

 panicle somewhat rigid ; outer palea only three-ribbed .: — whereas 

 m P, nemoralis the ligule is ven," short, scarcely perceptible ; panicle 

 long and slender ; oi/f«-^aZea five-ribbed. (Plate XX X^l.) 



From Poa ccBsia, in the uppermost joint being about the centre of the 

 stem : florets webbed : outer palea only three-ribbed ; — whereas in 

 P. ccEsia the upper joint is situated near the base of the stem ; florets 

 perfectly free : oM/er /j^Zea five-ribbed. (Plate XL.) 



Were it not for the small quantity of foliage that this grass pro- 

 duces, it would rank as one of the most valuable grasses, as it shoots its 

 leaves early in spring, and possesses a large share of nutritive pro- 

 perties. It grows naturally on dry poor soils, and is found in stony 

 places and wall-tops. 



It is a frequent grass in Scotland, England, and Ireland, also a 

 native of Norway, Sweden, Prussia, Germany, France, Switzerland, 

 Italy, Russia, Greenland, Iceland, and the northern parts of North 

 America. Attains an elevation of 3000 feet above the sea. 



Flowers in the second week of July, and the seed is ripe about the 

 middle of August 



00. Poa alpena.* 

 Alpine Meadow-Grass. 



Specific Characters. — Florets not webbed. Outer palea three- 

 ribbed. Glumes three-ribbed. Upper leaf folded, and shorter 

 than its sheath, Rachis and branches rough, (Plate XXX ^TI.) 



* Poa alpina^ Hooker, Smith, Kcch, Liad. 

 F 



