PLANTS AS DISEASK PRODUCERS 303 



Loranthus, Phoradendron and Viscum include the well-known mistletoes. 

 The American mistletoe, Phoradendron flavescens (Fig. 119), extends 

 from southern New Jersey, Maryland, Ohio, Indiana and Missouri 

 to Texas. It is a slow-growing green parasite, which on account of its 

 chlorophyll is not entirely dependent upon its host for its carbohydrates 

 (Figs. 120 and 121). It is essentially a water parasite, and consequently, 

 its parasitic roots or sinkers grow into the woody cylinder of its host, 



Fig. 120. — Cross-section of a live oak branch showing five stems of mistletoe 

 parasitic upon it. Note sinkers on parasitic roots penetrating into oakwood. (From 

 Gager.) 



where they spread out circumferentially (Figs. 120 and 121). The 

 white berries, which are sticky, are carried by birds as the sticky 

 mass containing the seeds adheres to the biU and is only removed 

 by rubbing the beak against the bark of a tree, for example. 

 Mistletoe does not kill the trees directly, but it often causes them to 

 become very much dwarfed and their branches distorted greatly. 



