TIIALLOPIIYTES: FUNGI 



79 



plant. In other words, a Lichen is not an individual, but a 

 firm of two individuals very unlike each other. This habit 





Fig. 70. A common lichen {PMjscia) growing on bark, showing the spreading thallus 

 and the numerous dark disks (apothecia) bearing the asci.— Goi.dberger. 



of living together has been called spnbiosis, and the indi- 

 viduals entering into this relation are called symhionts. 



Fig. 71. A common foliose lichen (Pannelia) growing upon a board, and showing 

 apothecia.— GoLUBERGEu. 



