GROWING ALFALFA SEED. 443 



low trefoil were imported and practically all was used to adul- 

 terate alfalfa and red clover seed. 



Chilean Lucern. Under the name of Chilean lucern, or luzerne, 

 burr clover is used as an adulterant if alfalfa seed in Germany 

 and has recently been found in seed offered for sale in the United 

 States. It is obtained from the woolen factories in Germany 

 which use Chilean wool. Burr clover grows abundantly in Chile, 

 and the burrs catch in the wool as the sheep are pasturing. In 

 the process of combing the wool the burrs are removed, and the 

 seed is afterwards cleaned and put on the market to be used 

 as an adulterant of alfalfa seed. 



This seed is similar to that of alfalfa in shape, and though 

 slightly larger and lighter in color, it lends itself most readily to 

 use an an adulterant. There are two species occurring- in about 

 equal quantities, which are apparently the ones common on the 

 Pacific coast of the United States (Medicago arabica and Medicago 

 denticulata) . 



Color of Dead Seed. A mixture of dead seed can easily be de- 

 tected by the color. Fresh seed which will grow is light olive- 

 green and when rubbed in the hands gives a bright, glossy sur- 

 face. Whenever alfalfa seed is any shade of brown it will not 

 grow and is worthless. If a sample contains any considerable 

 percentage of discolored seed it should not be accepted. 



Weed Seeds. The best grades of alfalfa seed contain com- 

 paratively few weed seeds. The low grades, however, which are 

 mostly screenings, often carry large numbers of weed seeds. 

 Dodder is the weed most destructive to the alfalfa plant. It is 

 a parasite having no leaves and appears as a tangled mass of fine 

 yellow stems winding about and clinging to other plants. The 

 seed germinates in the ground and sends up a slender stem that 

 winds around the alfalfa plant to which it attaches itself. The 

 dodder root soon dies, while the stems continue to grow and 

 thrive on the juices of the alfalfa until it has matured seed or 

 the alfalfa has been killed. 



Dodder occurs over most of the area where alfalfa is grown, 

 except in the extreme northern states. When once established ft 

 is very destructive and difficult to get rid of. The only effectual 

 way to combat it is to mow the infested area and burn the cut- 

 ting. There are two species which are about equally common 

 and destructive to alfalfa and red clover. The seeds of these 

 are of nearly the same size and are not easily distinguished. 

 The larger dodder seeds approach the smaller alfalfa seeds in 

 size and therefore are difficult to clean out thoroughly. In buy- 

 ing alfalfa seed it is essential to know that it is free from dodder. 



