SWEET CLOVER: GROWING THE CROP. 9 



has not been determined whether this is a distinct species or merely 

 an annual strain of the species mentioned. 



BIENNIAL YELLOW SWEET CLOVER. 



Biennial yellow sweet clover ordinarily is referred to in the seed 

 trade and among farmers in regions where it is grown simply as 

 yellow sweet clover. The plants of this species are somewhat 

 smaller, more decumbent the first year, and ordinarily with more 

 deeply notched leaves than the white-flowering species. Yellow 

 sweet clover usually grows from 3 to 5 feet in height. This plant 

 blooms from 10 to 14 days earlier than the white species, and for this 

 reason it is advisable to sow seed of both plants when they are to be 

 used for bee pasturage. On account of the finer stems of yellow 

 sweet clover it is preferred in some localities for hay, but since it 

 does not produce as much forage as white sweet clover and there is 

 much less demand for the seed, it constitutes only a very small per- 

 centage of the total acreage. The much larger root growth of the 

 white species, as illustrated in figure 5, is desirable because of the 

 additional quantity of humus added to the soil. 



The seeds of the yellow species may usually be distinguished from 

 those of other species, as some of them are slightly mottled with 

 purple. The shape of the calyx, which is generally present on un- 

 hulled seed, and the venation of the seed pods also distinguish it. 

 (See fig. 1.) 



ANNUAL YELLOW SWEET CLOVER. 



Annual yellow swe^t clover, more commonly known as sour clover 

 or bitter clover, is found chiefly in the South and Southwest. This 

 plant is considered a noxious weed in grain fields throughout the 

 Southwest. It is claimed that the flavor of the seed which is im- 

 parted to wheat can not be removed. Bakers decidedly object to 

 this flavor, stating that it injures bread. Sour clover is grown rather 

 extensively as a green-manure crop in orchards in portions of Ari- 

 zona and southern California and when properly handled in these 

 regions it has given profitable results. As the seed is obtained from 

 the screenings of wheat, it is offered on the market at a very low 

 price. Occasionally it is sold for the yellow biennial sweet clover. 

 Seed of this plant should not be sown in any part of the United 

 States except the extreme South or Southwest, and then only as a 

 green hay manure crop. Where it is desired to plant sweet clover 

 for pasturage or for the biennial white or biennial yellow species, 

 should be used. 



OTHER SPECIES OF SWEET CLOVER. 



Thirteen species of sweet clover have been tested by the Office of 

 Forage-Crop Investigations to determine their economic value. With 

 74950 Bull. 79717 2 



