254 DISEASES OF TROPICAL PLANTS CH. 



These brooms frequently die in advance of the tree, 

 which then assumes a very ragged and ugly appearance. 

 While it may not be practical to treat this class of 

 diseases in a forest, they can be treated in orchards and 

 on ornamentals. They should be pruned out and burned. 



Other Fungi. There are many other fungi which 

 attack the roots and stems, some few of which have 

 been referred to in previous chapters. Our limited 

 knowledge of these organisms and the diseases caused 

 by them make it impossible to give a discussion of them 

 at this time, even were it advisable to do so in a work 

 of this kind. 



Epiphytes. These plants grow upon many of our 

 forest and cultivated trees, using them as supports, but 

 not feeding upon them. They are not parasites in any 

 sense of the word, but do cause considerable injury by 

 interfering with the normal physiological activities of 

 the trees. 



Climbing and Smothering Plants. Climbing plants 

 sometimes destroy young trees and kill parts of matured 

 trees by compressing the parts to which they cling, and 

 interfering with or shutting off the passage of the plant 

 fluids and foods through its growing parts, in which 

 case all of that part of the plant beyond the point of 

 compression dies. 



Many tropical trees are checked in their growth or 

 killed by other plants which grow over and smother 

 them. In some cases the seed of a rapid-growing plant 

 germinates on some part of its victim and sends out root 

 growths which eventually reach the ground. In the 

 American tropics the seeds of certain species of Ficus 

 frequently lodge at the base of the leaves of the palms, 

 germinate, sending roots to the ground and branches 

 upward and eventually completely enclose the trunk of 

 the palm, which continues to grow, giving the appear- 

 ance of a double tree. 



Mistletoe. These partly green, flowering plants are 

 common not only in the tropical, but also in semi- 

 tropical and temperate climates. They are only 



