80 GRASSES OF SCOTLAND. 



common in certain localities. It is frequently met with in England and 

 Ireland. It is also a native of Lapland, Norway, Sweden, Denmark, 

 Prussia, Germany, France, Spain, Italy, North Asia, Iceland, and 

 the United States. Its limit of altitude seems about 1500 feet above 

 the sea. 



Flowers in the third week of June, and ripens its seed in the last 

 week of July. 



54. POA COMPRESSA. * 



Flat-stalked Meadow-Grass. 



Specific Characters. — Florets webbed. Outer palea three-ribbed ; 

 the marginal ribs hairy. (Plate XXX VII.) 



Description. — Its usual height is about a foot. The root is peren- 

 nial, creeping. Stem erect, decumbent at the base ; scarcely smooth ; 

 very much compressed ; rather stout, and somewhat contracted under 

 the panicle ; bearing four or five leaves, with smooth, striated sheaths ; 

 the upper sheath short, about the length of its leaf, crowned with a short 

 obtuse ligule. Joints five, smooth. Leaves rather short, flat, acute ; 

 rough on the inner surface and edges, smooth behind. Inflorescence 

 mostly simple panicled. Panicle somewhat unilateral, erect, spreading 

 while flowering, close both before and afterwards ; branches short and 

 rough, generally in pairs, the lowermost rather remote. Spikelets 

 ovate, acute, compressed, of five to seven florets ; the summit of the 

 lower floret scarcely extending beyond the large glume of the calyx. 

 Calyx of two nearly equal acute glumes (Fig. 1), often tinged with 

 purple ; three-ribbed, toothed on the upper part of the central rib. 

 Florets of two palese (Fig. 2) ; the outer palea of lowermost floret 

 three-ribbed, the lower half of the dorsal and marginal ribs hairy ; the 

 base furnished with a delicate loeb suspending the calyx (Fig. 4). In- 

 ner palea with two green marginal ribs minutely fringed. The whole 

 plant is of a darkish green. 



Obs. — Poa compressa, from its very flat stem, short sheaths, three- 

 ribbed outer palea, and webbed at the base, will readily be distinguish- 

 ed. It is more closely allied to Poa polynoda than to any other, but 

 differs from it in the lower florets being webbed ; outer palea three 



* Poa compressa, Linn., Koch, Leers, Schrad. Smith, Hooker, Lindle^-. 



