CRIMSON CLOVER AND OTHER ANNUALS 439 



tion, but apparently spotted bur clover is better adapted 

 to the conditions in the Southern States. It is quite 

 certain that it is more resistant to winter cold, withstand- 

 ing a temperature of about 15 F. without injury. Its 

 area of usefulness extends from North Carolina to Arkansas 

 and southward, both on sandy and clayey soils. 



Bur clover maybe sown anytime from August to Novem- 

 ber. If the seed is hulled, it should be sown at the rate of 

 15 pounds an acre and harrowed in lightly. In the bur 

 the seed weighs 10 pounds to the bushel, and two bushels 

 should be sown to the acre, harrowing or brushing it in 

 lightly. When sown in the bur, the resultant plants are 

 nearly always abundantly noduled, but this is seldom the 

 case when hulled seed is planted in new ground. Bur 

 clover reseeds itself readily, even if the ground is plowed in 

 late May or June for a summer crop, but it is never trouble- 

 some as a weed. Its use for winter pasturage in the South 

 is increasing. 



Commercial seed of spotted bur clover occurs as yet 

 only in the bur and often contains much straw and other 

 trash. The seeds are raked up from the ground after the 

 plants have become thoroughly dry so that the pods readily 

 detach. 



DAKOTA VETCH (Hosackia americana or Lotus americanus) 



529. Dakota vetch is a close relative of bird's-foot 

 trefoil and has been called prairie bird's-foot trefoil. It 

 is native to the western United States from Minnesota 

 and Arkansas west to the Pacific. It is especially abun- 

 dant in the Pacific States. The plant is a slender-stemmed, 

 loosely branched annual, growing 12 to 24 inches high ; 

 leaves trifoliolate ; flowers small, yellow and red ; pods 

 linear, pendent. 



