.«§ 



19a. Ligule about .2 mm. long 



80. Eragrostis spectabilis — Purple Lovegrass 



Leaves rolled in bud-shoot; sheath round, smooth with a tuft of hairs 

 at throat, split with overlapping hyaline margins; auricles absent; collar 

 broad, ring of hairs at base; ligule a fringe of hairs, about .2 mm. long; 

 blade 8 to 10 mm. wide, long hairy near base above, smooth below, mar- 

 gin rough and hyaline. Inflorescence — a diffuse, bright purple panicle 

 two-thirds entire height of plant. Throughout. Sandy soil. 



19b. Ligule at least .4 mm. long 20 



Wm 



m 



m 



20a. Sheath distinctly flattened . . . 

 20b. Sheath not distinctly flattened 



21 



81. Tridens flavus — Purpletop 



Leaves rolled in bud-shoot; sheath round, smooth, sometimes hairy at 

 top, split with overlapping margins; auricles absent; collar broad, hairy; 

 ligule a fringe of hairs, .4 to .8 mm. long; blade 8 to 17 mm. wide, hairy 

 above, smooth at least near base below, margins at least slightly rough. 

 Inflorescence — an open purple or nearly black panicle. New Hampshire 

 south. Old fields. 



21a. Plants with short knotty branching rhizomes 



82. Setaria geniculata — Knotroot Foxtail 



Leaves rolled in bud-shoot; sheath distinctly flattened, smooth, split 

 with overlapping hyaline margins; auricles absent; collar medium broad, 

 hairy on margins; ligule a fringe of hairs, .4 to .8 mm. long; blade 5 to 

 1 1 mm. wide, hairy above at least on lower half, keeled and smooth be- 

 low at least near base, margins smooth to slightly rough and hyaline. In- 

 florescence — dense, bristly, cylindrical, yellow or purplish, erect, spike- 

 like. Massachusetts south. Open ground, cultivated soil, pastures, moist 

 ground and salt marshes. 



21b. Plants without rhizomes 



83. Setaria lutescens — Yellow Foxtail 



Leaves rolled in bud-shoot ; sheath distinctly flattened, keeled, smooth, 

 sometimes sparsely hairy at base, split with overlapping hyaline margins; 

 auricles absent; collar narrow to broad, divided, hairy on margins; 

 ligule a fringe of hairs, .5 to 1 mm. long; blade 5 to 10 mm. wide, smooth 

 to slightly rough above and mostly with a few long hairs near base, 

 smooth below at least near base, margins at least slightly rough. Inflo- 

 rescence — dense, bristly, cylindrical, yellow, erect, spike-like. Common 

 throughout. Cultivated soil and waste places. 



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