518 ALFALFA FARMING IN AMERICA. 
been fully demonstrated whether the hardy char- 
acteristics of the Grimm and Siberian varieties pre- 
dominate in a cross. In some cases their peculiar 
habits of growth and some of their other character- 
istics, such as color of blossom, seem to predominate 
over like characters in a cross with the common 
alfalfa. Since alfalfa is a cross-fertilized plant it 
will obviously be impossible to grow these varieties 
on a large scale, so that the seed can be distributed 
to farmers in general without some crossing with 
the common alfalfas. In order to prevent this the 
plants grown for seed would have to be isolated 
from neighboring fields by means of wire screens to 
keep away bees and other insects, and obviously this 
is impracticable when the work is to be carried on in 
a commercial way. However, the farmer need not 
worry over this point, so long as his seed comes 
from the northwest. The severe winters and dry 
summers there will tend to keep weeded out the 
weaker strains, especially where the meadows are 
left standing for a great many years, as is now the 
eustom in Montana and the Dakotas. It is not un- 
common there to find a meadow 10 years old and 
there are several that have been proved to be over 
30 years old. So long as our seed comes from that 
region it is sure to be hardy, and we have evidences 
that some of the other characteristics of the newer 
varieties are dominant and that we will therefore be 
able to maintain these characters in spite of contin- 
ual crossing with the common alfalfas. 
