TIIALLOPHYTES : FUNGI 



295 



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

 firm of two individuals very unlike each other. This habit 



F,o 270 A common lichen (PkysdU) growing on bark, showing *£»«-*£^ 

 and the numerous dark diske (apothecia) bearmg the asc-GoLDRERGER. 



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

 viduals entering into this relation are called symbionts. 



Fig. 2T1. 



L common foliose lichen (Parmdia) growing upon a board, and showing 

 apothecia.— Goldberger. 



20 



