THE STORY OF THE LICHENS m 



character of lichens which could not but satisfy 

 even the most sceptical. In the course of the 

 investigation it was still further demonstrated 

 that not infrequently more than one kind of 

 algae might be embraced by the lichen, each 

 one being an easily recognised species. 



We have seen that in the lichen alliance it is 

 the algae which carry on the business of supply- 

 ing the growth with nutriment ; but the fungus 

 looks after the not less important matter of 

 attending to the scheme of reproduction. This 

 is brought about in two ways, the first of which 

 consists in the mere production of spores on 

 a part of the fungus. These tiny bodies are 

 produced in fructifications which often form 

 rather an attractive feature in a species of 

 lichen. The common Old Man's Beard Lichen 

 (Usnea) bears disc-Hke processes wherein are 

 produced spores or, as it sometimes happens, 

 bundles of spores. Like the spores of indepen- 

 dent fungi, these are very Hght, and float away 

 on the breezes. Such a large number are sent 

 out that it is almost certain that some of 

 them will be thrown into contact with algae, 

 which we have seen are almost everywhere. 

 Under suitable conditions of moisture the union 



