Commensalism with Continuous Contact 



375 



This is the forest primeval. The murmuring pines and the hemlocks, 

 Bearded with moss, and in garments green, indistinct in the twilight, 

 Stand like Druids of eld, with voices sad and prophetic. 

 Stand like harpers hoar, with beards that rest on their bosoms. 



Each of these mosses consists of two species forming a lichen, and 

 this grows as an epiphyte upon the conifers, thus creating a three-way 

 partnership. Epiphytes sometimes show chstinct preferences for one 

 host species, as may be seen, for example, in southeastern United 



rhol,, by H. B. Mnore 



Fig. 10.7. Bromeliads, including the pendant Spanish moss ( Tillaiulsia ) , growing 

 as epiphytes on the branches of the live oak in Florida. 



States where the Spanish moss grows more abundantly on the live 

 oaks than on the pines (Fig. 10.8). 



All these epiphytes use the trees only as a point of attachment amid 

 suitable light and other conditions, and manufacture their own food 

 by photosynthesis. Since they do not obtain nourishment from the 



