33° 



STRUCTURE AND LIFE HISTORIES 



Fig. 238. — A lichen, Parmelia perlala (,L.) Acli. i. Plant, slightly 

 reduced in size; a, apothecia', h, lobe of thallus; c, soredial patches. The 

 soredia are vegetative reproductive bodies composed of both algal and fun- 

 gal elements, and therefore able to reproduce the lichen; the ascospores, 



