GRAM IN ACE ;. 441 



Glumes 2, pointless, shorter than the flowers. Palese nearly 

 equal, membranaceous, awnless, often with a villous web at the 

 base ; the lower one keeled or concave ; upper one 2-keeled. 

 Stigmas simply plumose. Caryopsis free. Spikelets in diffuse 

 or contracted panicles. 



* Flowers webbed at base. 



1. P. pungens Nutt.: culm compressed; leaves very short, cuspidate ; 

 panicle somewhat simple, spreading ; spikelets lance-ovate, 3 4-flowered, 

 crowded at the extremities of the branches ; flowers rather obtuse. P. 

 flexuosa Muhl. 



Rocky woods. N. Y. to Car. April, May. Tj.. Culm 12 feet high, com- 

 pressed, smooth, somewhat cespitose. Leaves erect, cuspidate ; the radical ones 

 long, linear ; those of the culm usually 2, very short. Panicle small, semiver- 

 ticillate. Sharp-leaved Meadow-grass. 



2. P. pratensis Linn.: culm terete, smooth; leaves keeled, linear, ab- 

 ruptly acute ; ligule short, truncate ; panicle somewhat crowded, finally 

 spreading ; spikelets oblong-ovate, about 4-flowered ; flowers acute, 5- 

 nerved. P. viridis Mufd. 



Fields and meadows. Can. to Car. May July. 7J.. Root creeping. Culm 

 2 3 feet high. Leaves deep green, the lower very long, the upper much 

 shorter. Panicle at length pyramidal, spreading. Introduced from Europe. 



Smooth-stalked Meadow-grass. 



3. P. trivialis Linn. : culm and sheaths somewhat rough ; ligule elon- 

 gated, acuminate ; panicle equal, diffuse ; spikelets oblong-ovate, 2 3- 

 flowered ; flowers 5-nerved. P. stolonifera Muhl. 



Wet meadows. N. Y. lo Del. June Aug. r l\. Root fibrous. Culm 23 

 feet high, often stoloniferous at base. Leaves very narrow, pale green. Pan 

 icle large, pyramidal, the branches somewhat whorled. 



Rough Meadow-grass. 



4. P. compressa Linn. : culm decumbent or oblique, much compressed, 

 smooth; panicle contracted, somewhat secund; spikelets ovate-oblong, 

 4 8-flowered ; flowers obscurely nerved. 



var. sylvestris Torr. : culm slender, nearly erect ; panicle loose, somewhat 

 spreading ; spikelets 2 3-flowered. 



Fields and pastures. N. Eng. N. Y. and Penn. June, July. 7}.. Root 

 creeping extensively. Culm 12 18 inches high, often decumbent and rooting 

 at base. Leaves short, smooth, and with the culm bluish-green. Panicle con- 

 tracted, at first almost spike-like, finally a little expanding. Introduced from 

 Europe. Blue-grass. Wire-grass. 



5. P. serotina Ehrh. : culm erect, smooth ; panicle elongated, diffuse, at 

 length somewhat nodding at the top; spikelets ovate-lanceolate, 2 3- 

 flowered ; flowers yellowish at the tip, obscurely 5-nerved. P. palustris 

 Muhl. 



Wet meadows. N. Eng. and N. Y. June. 4 Root creeping. Culm 2? 

 feet high. Leaves flat, smooth. Panicle 6 10 inches Ion? ; the branches mostly 

 whorled in fives, rough and flexuous. Red-top. 



6. P. nemoralis Linn. : culm and leaves smooth : ligule almps* wanting; 

 panicle slender, a little attenuated, loose ; the branches rougb anJ tlexuous; 



19* 



