296 



examples, 'while of the latter Usnca, Parmelia (Fig. 202), 

 and Sticta (Fig. 201) may be taken as illustrations. 



Pig. 202.Parmflia aipolia. A, a portion of a tliallu.* with two apothecia, a/>, 

 and several spermagonla. , . J?, transverse section of thallus through an apotho- 

 cium ; cc, cortical layer of pwiido-parenclmiia ; </, </, sronidia! layers; an, medul- 

 lary layer ; h.h. hypotheciuni ; t,t.t.t.i\w hym.-niiini ; ft, asci (llu-ca-i, with 

 ascogpores. C, section through three ipenMgMta, t.f,*; rh,rh, rhixoids. I>, 

 i-torigmata from the interior of a pperinagonium, hearing ppermatia, *', *'. Aftei 

 Tulasne. 



