26 GBAMINEAE (GRASS FAMILY) 



out. Professor Spillman succeeded in cleansing a plot of Johnson- 

 grass in one year, without loss of the use of the ground, by a sys- 

 tem of fall plowing, with a turning plow capable of turning every 

 inch of the sod, harrowing thoroughly for the purpose of loosening 

 the soil, and then removing the rootstocks with an implement called 

 a root-digger, or grass-hoe. This method is discussed in detail in 

 Bulletin 72 of the Bureau of Plant Industry. 



CRAB-GRASS 



Digitaria sanguinalis, Scop. 

 (Syntherisma sanguinalis, Nash.) 



Other English names : Finger Grass, Polish Mil- 

 let, Purple or Large Crab-grass. 



Introduced. Annual. Propagates by seeds and 

 by rooting at the lower joints. 



Time of bloom : July to September. 



Seed-time: August to October. 



Range : Throughout the world. 



Habitat : Cultivated ground, waste places. 



The seeds of this grass must be very long- 

 lived, for, though it is never sown, let the 

 ground be cultivated, and as a general thing 

 Crab-grass will be there. In the Southern States 

 this is regarded as a good thing, for the spon- 

 taneous growth of the grass in grain fields after 

 harvest often yields a heavy crop of nutritious 

 hay and good pasturage after that. It is in 

 gardens, lawns, and cultivated ground that 

 the plant makes itself a plague, particularly in 

 a moist season. (Fig. 5.) 



Culms one to four feet long, decumbent or 

 creeping at base, and putting forth roots wher- 

 ever the joints are in touch with moist soil. 

 Sheaths and basal part of the blades rough and 

 more or less hairy, the blades three to six inches 

 long and a quarter to a half -inch wide. Spikes 

 grass (Digitaria saw- usua ^y three to six in number but occasionally 

 guinalis). x \. as many as ten, two to five inches long, gener- 



