PLATE III. 



Histology of a Foliose Lichen. 



{Sticta amplissinia.) 



\. Vertical section through apothecium : 



a, b, thecium, consisting of the spore-sacs and para- 

 physes ; o, colored ends of paraphyses ; c, d, hypothe- 

 cium ; c, upper hyphal layer; d, lower cortical layer; e, 

 upper algal layer; /j medullary layer; g, lower algal 

 layer; h, cortical layer; /, rhizoids (aerial). 



2. Vertical section through thallus: 



a, epidermal layer ; b, upper cortical layer ; r, algal layer; 

 d, medullary layer ; e, lower cortical layer; /, rhizoids. 



3. Paraphyses and spore-sac more highly magnified. 



4. Spores highly magnified. 



5. Algae {Protococcus} and haustoria. 



1 and 2 magnified about 300 diameters ; 3, 4 and 5 more highly 

 magnified. 



