52 FARM FRIENDS AND FARM FOES 



conditions for their growth. In such cases rotation with a 

 hoed crop is desirable. 



THE PARASITIC DODDER 



All the weeds so far discussed in this chapter injure the 

 crop by robbing the soil of food and moisture, or by oc- 

 cupying the space above the soil to the exclusion of the 

 cultivated plants. There is one group of pernicious weeds, 

 however, which do more than this, for they actually attack 

 the green tissues of the crop and rob them of the life- 

 giving sap. These plants are commonly called Dodders, 

 and there are several species that attack different crops. 

 In their life history, however, they are very similar to one 

 another. 



The young Dodder plant starts from a seed well stocked 

 with nourishment. When the seed germinates, this nour- 

 ishment enables it to develop into a seedling which soon 

 comes in contact with the stalk of some green plant. 

 Then the little Dodder sends out from along the sides of 

 its own stalk curious rootlike projections that penetrate the 

 tissues of the other plant and draw out the sap. There is 

 thus established the relation of parasite and host : the 

 parasite is the Dodder sucking the life sap from its victim, 

 which is the host plant. The root and lower stem of 

 the Dodder soon wither. In the case of clover, which is 

 often infested by Dodder, the clover plant continues to 

 grow, having roots in the ground and leaves in the air, 

 but those clover stalks which are attacked by the Dodder 

 become dwarfed as well as hard and woody. 



As the Dodder grows, it constantly twines around more 

 stalks of its host plant, sending into their tissues more of 

 the rootlike suckers, and after a time developing small 

 blossoms which later mature into seed. As the Dodder is 



