15b. Plants not spreading by stolons 16 



16a. Collar narrow, divided 



49. Agrostis hiemalis — Spring Hairgrass 



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

 ping hyaline margins; auricles absent; collar narrow, divided, sometimes 

 indistinct; ligule membranous, 1 to 3 mm. long, rounded to acute; blade 

 1 to 3 mm. wide, smooth to rough above and below, margins at least 

 slightly rough. Inflorescence — a purplish, spreading, slender-branched 

 panicle. Massachusetts south. Open ground, fields and waste places. 



1 6b. Collar broad, not divided 



50. Eragrostis capillaris — Lacegrass 



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

 lapping hyaline margins; auricles absent; collar broad; ligule membra- 

 nous, 1 to 2 mm. long, rounded, lacerate or toothed; blade 2 to 3 mm. 

 wide, rough above and below and on margins. Inflorescence — an open, 

 diffuse panicle two-thirds entire height of plant. Throughout. Dry, open 

 ground and fields. 



GROUP 4 



1 a. Sheath long hairy, at least at top or throat 



51. Echinochloa walteri— Walter's Millet 



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

 and long hairy at least at top or throat, split with overlapping hyaline 

 margins ; auricles absent ; collar narrow to medium broad ; ligule absent ; 

 blade 10 to 20 mm. wide (sometimes to 30 mm.) , rough above and below 

 at least near tip, margins rough to very rough and hyaline. Inflorescence 

 —a compact panicle with short, bristly, densely flowered, spike-like 

 branches. Coastal Plain. Massachusetts south. Wet places, often in 

 shallow water or brackish marshes. 



1 b. Sheath not hairy 2 



2a. A common weed 



52. Echinochloa crusgalli — Barnyard Grass 



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

 mostly smooth but occasionally somewhat rough or short hairy, split to 

 base with overlapping hyaline margins; auricles absent; collar narrow to 

 broad; ligule absent; blade mostly 10 to 20 mm. wide (occasionally to 30 

 mm.) , generally rough above at least near tip, margins rough. Inflores- 

 cence—* compact panicle with short, densely flowered, spike-like 

 branches. Throughout. Moist, open ground, fields and ditches. 



20 



