254 FIELD CROP PRODUCTION 



RED CLOVER 



252. History. This " Red Plumed Knight," as it has 

 been dubbed by one of its admirers, is a native of Persia, 

 and from there it spread through the greater part of 

 Europe, where for many years it has been an important 

 factor in the maintaining of a permanent system of ag- 

 riculture. It was introduced into Pennsylvania, probably 

 from Holland, almost 150 years ago. Since that time 

 the area of its culture has gradually extended and now it 

 holds a most important place in the esteem of the American 

 farmer. While it is most commonly known as red clover, 

 it is also known as broad-leafed clover, common clover, 

 medium clover, and medium red clover. It is called 

 medium clover or medium red clover to distinguish it 

 from the mammoth clover, which it closely resembles. 



253. Description. Red clover, Trifolium pratense, 

 is the most commonly grown and is perhaps the most 

 valuable species of the genus Trifolium. It has a large, 

 well-developed root system, made up of a tap root, which 

 may extend several feet into the ground, and numerous 

 lateral branches which grow out from it a few inches below 

 the surface of the ground. The tap root grows almost 

 directly downward and undoubtedly is of great service to 

 the plant in obtaining water from the deep subsoil in 

 time of drought. Sometimes the tap root is broken off by 

 the alternate freezing and thawing during a severe winter, 

 and the plant, thus released from its anchorage, is pushed 

 up out of the ground for some distance. This is known 

 as heaving and is decidedly injurious to the plants, some- 

 times destroying entire fields of them. When the clover 

 plant is quite young, the crown, that is, the short stem 

 and top of the tap root, may be quite a little distance 



