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A TEXT-BOOK OF BOTANY 



It has been found that the lichen-alga can live quite 

 independently of the lichen-fungus. In fact, the enmeshed 

 Algae are often recognized as identical with forms living 

 independently, the forms usually being certain blue-green 



FIG. 158. Much enlarged section of portion of lining layer, showing the asci 

 (1, 2, 3, 4) with their contained spores. After SACHS. 



Algae and some of the simpler green Algae. On the other 

 hand, it has been found that the lichen-fungus is com- 

 pletely dependent upon the Algae; for the germinating 

 spores of the fungus do not develop far unless the young 



