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 :f 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 it 
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. 
