296 



BOTANT. 



examples, while of the latter TJsnea, Parmelia (Kg. 203), 

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



Kg. WSa.— Parmelia aipolia. A, a portion of a thallus with two apothecia, ap, 

 and several spermagonia. fi, fi. 5, transverse section of thallus through an apothe- 

 cinm ; cc, cortical layer of pseudo-parenchyma ; g, g\ gonidial layers ; cm, medul- 

 lary layer ; h. h, hypothecium ; t, t^ t, t, the hymenium ; t?i, asci (thecae), with 

 ascospores. C, section through three spermagonia, s.s,s; rh'.rh, rhizoids. D, 

 stcrigmata from the interior of a spermagonium, bearing spermalia, s\ «'. — After 

 Tulasne. 



