1^] first on the mountain top 



alga can also be found in nature living on its own. The 

 fungus seems always to have lost its power to survive in 

 nature except as one half of a partnership. Less than a 

 hundred years ago botanists first came to understand the 

 strange situation and for a while some remained skeptical 

 about it. But they were convinced when an experimenter 

 succeeded in actually synthesizing a lichen. He grew the 

 fungus and the alga separately. Then he brought them to- 

 gether to form a lichen different from either. 



This is not, be it noted, a case of parasitism. One plant 

 does not live off the other. What we have instead is one of 

 the closest and most striking cases of symbiosis, of living 

 together because living together is advantageous to both 

 organisms. The fungus, having no green chlorophyll, can- 

 not manufacture its own food from chemical substances 

 and it gets its organic nourishment from the green alga 

 which can. In return it protects the alga from drought and 

 collects the chemicals which the alga can turn into assimi- 

 lable food for both the partners. Competition and strife 

 are not the only laws of life. The algae are among the 

 oldest and most primitive of all living things. The evi- 

 dence of very ancient rocks indicates that they were flour- 

 ishing perhaps a billion years before any plant or animal 

 capable of forming a clearly outlined fossil had appeared. 

 Yet even an alga is able to cooperate as well as compete. 



Man has consciously used lichens in various minor ways. 

 One species furnishes a dye still used in the Highlands to 

 color homespun. Another supplies the essential substance 

 in the litmus paper of the chemist. On the northern tun- 

 dras the so-called "reindeer moss," as important to grazing 

 animals as grass in temperate climates, is really a lichen. 

 So too is the "Iceland moss" which Eskimos eat. Still an- 



