gi ALPAtPA 



C, a group of natural size. D, the embryo. These 

 illustrations were prepared with reference to showing 

 the likeness of some of these seeds to those of dodder. 

 When a field is once thoroughly seeded to dodder, 

 the only remedy is to plow up the alfalfa and cultivate 

 the land a few years to other crops. There are 

 numerous other species of dodder besides the one 

 referred to, but few of them attack alfalfa. If a small 

 patch is discovered, scatter dry straw or hay over the 



FIG. 18 — &BD CLOVER SEEDS FIG. I9 — WHITE CLOVER SEEDS 



patch and burn off. The straw scattered thinly destroys 

 the dodder, but will not injure the alfalfa. Bum in a 

 wind, and there is less danger of destroying the alfalfa. 



BACTERIA 

 The alfalfa plant has one parasitic friend that is of 

 the greatest importance to agriculture — namely, the 

 species of bacteria which inhabits the tubercles on the 

 roots of the plants. These microscopic organisms 

 dwell in harmony or symbiosis upon the roots. The 

 badteria take nitrogen from the air and feed the alfalfa 

 plant, which, in its turn, sends some elaborated food 

 down into the nodules for the maintenance of the bac- 

 teria. The adlivities of the millions of badteria, which 

 live in symbiosis with every healthy alfalfa plant, 

 enable the alfalfa to add marvelous stores of nitrogen 



