26 GRAMINEAE (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 sanguindlis, Scop. 
(Syntherisma sanguindlis, 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 
usually three to six in number but occasionally 
Fie. 5. — Crab- 
grass (Digitaria san- 
guinalis). xX 4. as many as ten, two to five inches long, gener- 
