g BULLETIN" 461, U. S. DEPARTMENT OF AGRICULTURE. 



BB. Sheaths laterally compressed. 

 C. Collar and sheath not hairy. 



D. Rootstocks or stolons present. 



E. Creeping stems (rootstocks) more than one-eighth inch in 

 diameter. 



31. Johnson grass (Andropogon halepensis). 

 EE. Creeping stems (stolons) less than one-eighth inch in 



diameter. 



32. Nimble Will (MuMeribergia sclireberi). 

 DD. Rootstocks and stolons not present. 



E. Ligule wanting. 



33. Barnyard grass (Ecliinocldoa crus-galli). 

 EE. Ligule present. 



- F. Ligule membranous. 



34. Sudan grass (Andropogon sorghum 



sudanensis) . 

 FF. Ligule a fringe of hairs. 

 G. Blades hairy above. 



35. Yellow foxtail (ChaetocJiloa lutescens). 

 GG. Blades not hairy. 



36. Spreading witch - grass (Panicum di- 



chotomiflorum ). 

 CC. Collar or sheath hairy (either or both). 

 D. Ligule membranous. 



E. Sheaths white, with pink nerves. 

 F. Ligule entire, hairy on the back. 



37. Rescue grass (Bromus unioloides). 

 FF. Ligule toothed on margin, not hairy on the back. 



38. Velvet grass (Holcus lanatus). 

 EE. Sheaths pale, without pink nerves. 



F. Stolons present. 

 G. Sheaths hairy. 



39. Crab-grass (Syntlierisma sanguinalis) . 

 GG. Sheaths not hairy. 



40. Small crab-grass (Syntherisma iscJiae- 



mum) . 

 FF. Stolons not present. 



G. Habit of growth low and decumbent at the base. 



41. Field paspalum (Paspalum laeve). 

 GG. Habit of growth upright. 



42. Smooth paspalum (Paspalum dilatatum) . 

 DD. Ligule a fringe of hairs. 



E. Rootstocks present. 



43. Bermuda grass (Capriola dactylon). 

 EE. Rootstocks not present. 



F. Sheaths hairy. 



G. Collar hairy on the back. 



44. False redtop (Tridens fldvus). 

 GG. Collar not hairy on the back. 



45. Green foxtail (Chaetocliloa viridis). 



