GRASSES OF SCOTLAND. S5 



Second sheath not reaching to the first joint. Outer palea five-rib- 

 ed. Glumes acute^ three-ribbed. (Plate XXXIX.) 



Description. — It grows from twelve to eighteen inches high. The 

 root is perennial, creeping. Stem ascending, procumbent at the base, 

 compressed, scarcely smooth, bearing six or seven leaves, with short 

 smooth striated sheaths : the upper sheath about equal in length to its 

 leaf, situated far up the stem, crowned with a short, obtuse ligule (Fig 

 5) ; second sheath not reaching to the first joint. Joints six or seven, 

 smooth ; the uppermost joint near the panicle. Leaves mostly all on 

 the stem, short, flat, acute, roughish on the edges and inner surface, 

 smooth behind. Inflorescence panicled, erect, of an ovate-lanceolate 

 form, with short rough branches, arranged on the rachis mostly in 

 pairs. Spikelets small, ovate, of four or five awnless florets ; the siun- 

 mit of the lowermost floret not extending beyond the large glume of 

 the caK-x. Calyx of two acute nearly equal glumes (Fig. 1), three- 

 ribbed, the dorsal rib minutely toothed on the upper half. Florets 

 not icebbed; of two paleae (Fig. 2) ; the outer palea of lowermost floret 

 Jive-ribbed (Fig. 4) ; the lower half of the dorsal and marginal ribs 

 but slightly hairy ; the intermediate ribs naked and rather indistinct. 

 Inner palea rather shorter than the outer palea, with two green 

 marginal ribs delicately fringed. The whole plant is somewhat 

 glaucous. 



Obs. — Poa pohjnoda difiers from Poa ccEsia, in the stem bearmg 

 six or more joints ; the upper joint near the panicle ; second sheath 

 not reaching to the first joint, and the summit of the lowermost floret 

 not extending beyond the large glume of the calyx ; — whereas in P, 

 casia the stem bears but two joints ; the uppermost joint situated near 

 the base, leaving two-thirds of the stem naked ; second sheath cover- 

 ing the first joint, and the summit of the lower floret projecting be- 

 yond the large glume of the cal}-x. (See Plate XL.) 



From montana, in panicle being short and rigid ; upper joint of the 

 stem near the panicle ; summit of the lower floret extending beyond 

 the large glume of the calyx ; — whereas in P. montana the panicle is 

 long and slender; upper joint situated about the centre of the stem ; 

 summit of the lower floret not projecting beyond the calyx. (See 

 Plate X:^:XIX.) 



From Poa compressa, in the fiorets not being webbed, and the outer 

 palea fiAe-ribbed ; — whereas in P. compressa the loicer fiorets are dis- 



