172 Graminese. 



658 Stems stout, 659 



658 Stems very slender, . , . . , P. nemoralis. 



659 Leaves linear, P. pratensis. 



659 Leaves short broad mucronate, ..,.,. P. alpina. 



PO'A TRIVIA'LIS (108). Roughish Meadow Grass. 6—7. Stem and 

 (171 1 ) leaves rough, panicle green much-branched spreading, spikelets ovate 

 of 2 — 3 florets connected by a web. Meadows. 



PO'A AN'NUA (no). Common Meadow Grass. 3—10. Stem com- 

 (1700) pressed smooth, leaves linear obtuse, panicle spreading, spikelets 5 — 6- 

 flowered without a web^ Everywhere. 



PO'A COMPRES'SA (69). Flat-stalked Meadow Grass. 6—7. Stem 

 (1708) compressed 6 — 8 in., panicle somewhat one-sided close, spikelets of 

 5 — 7 florets webbed or not. Dry banks and walls. 



PO'A NEMORA'LIS (82). Wood Meadow Grass. 7—8. Stem and 

 (1707) leaves smooth, panicle loose slender nodding, spikelets of 3 — 5 florets, 

 paleae pubescent on edges and keel. Woods. 



PO'A PRATEN'SIS (108). Smooth Meadow Grass, d—^. Stem 1—2 



(1710) ft. round smooth, panicles 2 — 6 in. diffuse pyramidal, palese silky on 



edge and keel, spikelets of about 4 florets webbed. Meadozvs. 



Po'a alpi'na (15). Alpine Meadow Grass. 7 — 8. Stem 6 — 8 in. smooth 

 (1702) slightly compressed, panicle erect, spikelets erect 4 — 5-flowered, outer 

 palea deep purplish-red silky on the keel, leaves broad firm with 

 thickened edges mucronate. [G. [_Ingleborough.) 



XXXI.— CA TABROSA. 



CATABRO'SA AQUAT'ICA (86). Water Whorl-grass. Aquatic, stem 

 (1693) * — 2 ft., panicle long pyramidal with whorled branches, spikelets ovate 



awnless, empty glumes 2 very blunt upper one much the larger toothed 



at the tip, palese thick white. Watery places. 



XXXll.—GL YCERIA. 



Spikelets linear 3- or many-flowered in semi-whorled panicles, empty 

 glumes 2 unequal convex awnless, outer palea convex not keeled with entire 

 tip, inner palea bifid with ciliate nerves. 



Leaves with entire sheaths, 660 



Leaves with split sheaths, 661 



660 Panicle much -branched, .... G. aquatica. 



660 Panicle nearly simple, . . . . . G. fluitans. 



661 Empty glumes 3-nerved, G. maritima. 



661 Empty glumes i -nerved, G. rigida. 



