TRIANPRIA DYGINIA. 309 



P. pratensis: panicle diffuse; upper leaves much shorter than the 

 smooth sheaths ; florets acute, 5-nerved, webbed at the base ; stipule 

 short, truncate ; root creeping. 



HAB. Meadows and pastures. May July, 1|. ; panicle pyramid. ; 



spik. ovate ; glum, unequal. 



P. trivialis : panicle equal, diffuse, spikelets oblong-ovate, about 3- 

 flowered ; florets webbed at the base, 5-nerved ; culm sheaths rough- 

 ish ; stipule oblong ; root creeping. 



HAB. Moist meadows. June Aug. 'I].; culm 2 3 feet high, stolo- 



nif. ; panicle pyramidal ; stipule elongated. 



P. compressa : panicle contracted, somewhat secund ; spikelets oblong, 

 3 6-flowered ; florets webbed ; glumes .nearly equal ; culm oblique, 

 compressed ; root creeping. 



HAB. Fields and dry hills. June July, 1}.; culm afoot high, as- 

 surgent ; leaves glauc. ; panicle sub-spiked. 



b. sylvestris : panicle loose, spreading ; spikelets 2 3-flowered ; culm 

 slender, nearly erect. 



HAB. In dry woods. July. 



P. serotina: panicle elongated, diffuse, at length somewhat secund; 

 spikelets ovate-lanceolate, 2 3-flowered; florets a little webbed at 

 the base, yellow at the tip, obscurely 5-nerved ; root creeping. 



HAB. Wet meadows. June, 1].; culm 2 4 feet high; panicle op- 

 press, -when young ; calyx often 2-Jlowered ; anther yellow. 

 P. nemoralis : panicle attenuated, weak ; branches flexuous ; spikeleta 

 ovate, about 3-flowered ; florets loose, slightly webbed, acute, obso- 

 letely nerved ; stipule almost wanting. 



HAB. Rocky woods. July, If. ; pale green; panicle capillary; 



Jlorets at length distant. 



P. nervata : panicle equal, diffuse ; branches weak, and at length pen- 

 dulous ; spikelets 5-flowered ; florets free, conspicuously 7-nerved, 

 obtuse. 



HAB. In wet meadows and in ditches. June, 1|- ; culm 3 4 feet 

 high ; panicle large, many-flowered ; spik. ovate ; flowers decidu- 

 ous ; stamens mostly 2. 



P. elongata : panicle elongated, racemose ; branches solitary, appressed ; 

 spikelets ovate, obtuse, tumid, 3-flowered; florets free; stipule al- 

 most wanting. 



HAB. Wet meadows. June July, 1L ; culm 3 feet high, dark green ; 



panicles nodding ; flower 5-ncrved. 



P. canadensis : panicle large, effuse ; spikelets semi-verticillate, flexu- 

 ous, at length pendulous ; spikelets ovate, tumid, 5 8-flowered ; 

 florets free ; inferior valve somewhat acute, 7-nerved ; superior valve 

 very obtuse ; stamens 2. 



HAB. Swamps. July Aug. ^5 culm 3 4 feet high; leaves long; 

 panicle atflrst pyramidal, at length much spreading and pendu- 

 lous. 



P. hirsuta : culm erect, compressed, simple ; sheaths hairy ; panicle 

 very large, capillary ; branches expanding, at length reflexed, 

 bearded in the axils ; spikelets oblong, about 5-flowered ; corolla 

 ciliate on the margin. 



HAB. Sandy fields. July Aug. Tj. ; culm flrm, straight ; leaves 

 longer than the culm ; floicer purplish. 



b. spectabilis : spikelets linear, 10 15-flowered. 



HAB. Sandy fields on the sea-shore. Taller than the preceding; 

 spik. purple, i inch long. 



