82 MISC. PUBLICATION 200, U.S. DEPT. OF AGRICULTURE 



equal, short, obtuse or acute, usually scarious, mostly L-nerved (the second 

 3 nerved in :t few species); lemmas broad, convex on the back, firm, usually 

 obtuse, scarious at the apex, 5- to 9-nerved, the nerves parallel, usually 

 prominent. Usually tall aquatic or marsh perennials, with creeping and 

 rooting bases or with creeping rhizomes, simple culms, mostly closed or partly 

 closed sheaths, flal blades, and open or contracted panicles. Type species, Gly- 

 ceriafluitans. Name from the Greek glukeros, sweet, the seed of the typo species 

 being sweet. 



The species are all palatable grasses but are usually oi limited distribution, 

 and most of them are confined to marshes or wet land. Glyceria elata, tall 

 mannagrass, is a valuable component of the forage in moist woods of the 

 Northwestern States. G. striata, fowl mannagrass, widely distributed, a. 

 grandis, Ajnerican mannagrass, in the Northern States, and (5, pauciflora of the 

 Northwest are marsh species, but are often grazed. 



Spikelets Linear, nearly terete, usually l cm. long or more, oppressed on short pedicels; 



panicles narrow, erect Section 1. Euglyceria, 



Spikelets ovate or oblong, more or loss compressed, usually not more than 5 nun. long; 



panicles usually nodding Section 2. Hydropoa, 



>7(-/.v>; /. Euglyceria 



Lemmas acute, much exceeded by the palea I. 0. vornnouv. 



Lemmas obtuse; palea about as long as the Lemma (or slightly longer in G. septentrioncdis and 



Huitans). 



1 emmas glabrous between t ho slightly scabrous nerves - 2. G. bore u is. 



Lemmas scaberulous or hirtellous between the usually distinctly scabrous nerves. 

 Lemmas about 3 nun. long, broadly rounded at i ho summit. 



First glume t. 5 mm. long; lemmas scaberulous 3. 0. leptostachya. 



First glume 2 to 2.5 mm. long; Lemmas hirtellous 4. G. lrkansan \. 



1 lemmas 1 to 7 mm. long. 



Culms more than 60 cm., commonly more than 1 m. tall, flaccid; sheaths closed from 

 below the summit, blades elongate, mostly more than 5 mm. wide. 

 Lemmas pale or green, not tinged with purple, about & mm. long; palea usually 



exceeding the lemma; Eastern States ... 5. G. septentrionalis. 



1 emmas slightly tinged with purple near the tip, 5 to 6 mm. long; palea about as 

 long as the lemma, sometimes slightly exceeding it ; Northeastern States. 



6. G. fluitans, 

 Lemmas usually tinged with purple near the tip. I to nun. Long; palea rarely 



exceeding the lemma; Western States 7. G, OCCIDENTALIS. 



Culms 15 to 30 cm. tall, slender but rather firm; sheaths open, the margins overlap- 

 ping; blades with boat-shaped tip. 3 to o em. Long, 2 to ;> mm. wide. 



S. G. DECl iN.vr \. 



Section 2. Hydro 



Lemmas with 7 usually prominent nerves; second glume l-nerved: sheaths, at least the 

 upper, closed from below the summit. 

 Panicle contracted, narrow. 



1 emmas 3 to I mm. long; panicle oblong, dense, usually not more than 10 cm. long. 



n. G. OBTUSA. 

 Lemmas 'J to 2.5 nun. long; panicle rather loose, nodding, lo to 25 cm. long. 



L2. G, WEI 10 VKl \. 



Panicle open, Lax. 

 \ rves of lemma evident but not prominent 13. G. canadensis. 



Nerves of lemma prominent. 



Lost glume not more than I mm, long. 



3 2 to 4 mm. wide, sometim.es to S mm., rather firm, often folded; first glume 



0.5 mm. long n. G. striata. 



Blades 6 to L2 mm. wide, fiat, thin, lax; first glume about 1 nun. long. 



15. 0. BLATA. 

 First glume more than 1 mm. long, usually about Lo mm. long. 



Glumes SUOequal, blunt, pale, in striking contrast to the purple fiorets, 



9. G. ok LNDIS. 



