192 PLANT LIFE 



plant. Microscopic examination of a root 

 shows that they are permeated by fungal 

 hyphce, and careful experiments have proved 

 that it is through the intermediation of these 

 fungal threads that the saprophyte chiefly 

 obtains its food. It thus appears that the 

 term saprophyte is not a very happy one 

 as applied to a plant like Neottia. The 

 relation is rather more akin to parasitism, 

 and it is the fungus from which nourishment 

 is finally extorted. But inasmuch as the 

 root both houses the fungus, and also con- 

 tributes something towards its support, the 

 parasitism is not very one-sided, although 

 the final balance lies with the flowering plant. 



This association of the root with a fungus 

 is a very intimate one in a large number 

 of instances, and it occurs in a very great 

 number of plants which would never be sus- 

 pected of parasitic habits. The fungus-root 

 is often called a mycorhiza, and it is worth 

 while to study it a little more closely. 



The roots of many of our forest trees 

 produce few or no root-hairs. Instead of 

 this they are closely invested with a hairy 

 coating of fungal hyphge. Not only do these 

 hyphae ramify in the soil, but they also enter 

 the root itself. Sometimes, as in the pines, 

 they only pass between the cells, and do not 

 enter them, but in other cases, as for example 

 in orchids generally, they pierce the cell walls 

 and enter the living cells. In both of these 

 types of mycorhiza the fungus is doubtless 



