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STRUCTURE AND LIFE HISTORIES 



I ' 



FIG. 238. A lichen, Parmelia perlata (L.) Ach. i. Plant, slightly 

 reduced in size; a, apothecia; b, 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, 



