ROOT DISEASES AND INJURIES 85 



above, where all the food materials required by the plant are 

 obtained through the connected roots, include the common 

 beech-drop (see page 108), indian-pipe and many other plants 

 belonging to various families of the flowering plants. 



References 



Hedgcook, G. G. Parasitism of Comandra umbellata. Jour. Agr. 



Res. 6 : 133-135. 1915. 

 Harshberger, J. W. Vegetal agents of disease. In A text-book of 



mycology and plant pathology, pp. 298-306, figs. 117-123. 1917. 



