12a. Blade hairy above 



212. Elymus villosus — Hairy Wild-rye 



Leaves rolled in bud-shoot; sheath round, smooth, split with one over- 

 lapping margin hyaline and one hairy; auricles small; collar medium 

 broad, divided; ligule membranous, about .4 mm. long, truncate; blade 

 5 to 10 mm. wide, short hairy above and below, keeled near base below, 

 margins rough and hyaline. Inflorescence — a dense, bristly, drooping 

 spike. Vermont south. Shady and mostly damp places. 



12b. Blade not hairy above 



213. Elymus riparius — Riverbank Wild-rye 



214. Elymus virginicus — Virginia Wild-rye 



Leaves rolled in bud-shoot; sheath round, smooth or sometimes rough, 

 rarely short hairy, split with overlapping margins both hyaline or both 

 hairy or one hairy; auricles small; collar broad, divided; ligule membra- 

 nous, .2 to .6 mm. long, truncate; blade 5 to 14 mm. wide, rough above, 

 keeled and smooth to rough below, margins rough and hyaline. Inflores- 

 cence — a dense, bristly, erect spike. Throughout. Moist ground and 

 along streams. 



GROUP 17 



la. Plant with creeping rhizomes 2 



1 b. Plant without creeping rhizomes 3 



2a. Collar hairy on margins 



215. Muhlenbergia frondosa — Wirestem Muhly 



Leaves rolled in bud-shoot; sheath round to somewhat flattened, 

 smooth, split with overlapping hyaline margins; auricles absent; collar 

 broad, hairy on margins; ligule membranous, about 1 mm. long, rounded ; 

 blade to 8 mm. wide, rough above, rough below at least near tip, margins 

 rough. Inflorescence — numerous, slender panicles. Throughout. Not 

 common. Low ground and waste places. 



2b. Collar not hairy on margins 



216. Leersia virginica — Whitegrass 



Leaves rolled in bud-shoot; sheath somewhat flattened, rough and 

 hairy at base, split with overlapping hyaline margins; auricles absent; 

 collar narrow to broad ; ligule membranous, .6 to 1 mm. long, truncate, 

 may be toothed; blade to 10 mm. wide, rough above and below, some- 

 times short hairy below, margins rough. Inflorescence — an open panicle 

 with capillary branches distant. Throughout. Moist places. 



3a. Collar hairy at least on margins 4 



62 



