PLATE V {co7itinued). 



Fig. 



specimens of A. Smithii. Some of the specimens figured resemble 

 certain compound or cellular spores ; others might be mistaken 

 for empty gonidia. 



e. Stylospores retaining their sterigmata. They are of small size, and 



somewhat shrivelled. Those coloured yellow are from Highland 

 localities. 



f. Small yellow stylospores from Highland localities. 

 7. — Development of the stylospores from their sterigmata. 



a. Sterigmata. 



b. Stylospores. 



The sterigmata appear first as simple filaments, with a rounded 

 or bulging extremity ; this gradually becomes dilated and separated 

 from the sterigmata by a septum. The terminal cell then consti- 

 tutes the stylospore, which speedily falls off, aud for some time 

 increases in size, acquiring more of a pyriform shape. 

 8. — Portion of the thalline lacinise of P. saTatilis, showing the spermo- 



gones a, and the black-fibrillose under surface b. 

 9. — BuUose dilatation of thallus of Cetraria glauca, bearing the apotliecia 

 and spermogones of A, oxysporus. The section shows that it is 

 hollow and stipitate. 



