FAMILIES AND GENERA 337 



margin of the under surface, the tip of the fertile lobe in that case is turned 

 back as the apothecium matures, so that the fruit eventually faces the light. 

 In Nephroma has been included Eunephroma with bright-green gonidia and 

 Nephromium with blue-green. 



Bitter 1 has recorded the finding of apothecia on the under surface of 

 Peltigera malacea and not at the margin, as in Nephromium. The plant was 

 otherwise normal and healthy. Solorinella, from Central Europe and 

 Asteristion from Ceylon are monotypic genera with poorly developed thalli. 



Thallus poorly developed. 



Asci 6-8-spored; spores 3~5-septate ..................... I. ^Asteristion Leight. 



Asci many-spored ; spores i-septate ..................... 2. *Solorinella Anzi. 



Thallus generally well developed. 



Apothecia superficial, sunk in the thallus ............... 3. Solorina Ach. 



Apothecia terminal on upper surface of lobes ......... 4. Peltigera Willd. 



Apothecia terminal on lower surface of lobes ......... 5. Nephroma Ach. 



XLIV. PERTUSARIACEAE 



Thallus crustaceous, often rather thick and with an amorphous cortex 

 on the upper surface. Algal cells Protococcaceae. Apothecia solitary or 

 several immersed in thalline warts, generally with a narrow opening which 

 barely exposes the disc, and which in one genus, Perforaria, is so small as 

 almost to constitute a perithecium ; spores are often very large and with 

 thick walls; some if not all are multinucleate and germinate at many points. 



In the form of the fruit, this family stands between Pyrenocarpeae and 

 Gymnocarpeae, though more akin to the latter. Perforaria, with two species, 

 belongs to New Zealand and Japan. Pertusaria has a world-wide distri- 

 bution, and Varicellaria, a monotypic genus, with a very large two-celled 

 spore, is an Alpine plant, recorded from Europe and from Antarctic 

 America. 



Spores simple. 



Apothecia with pore-like opening ........................ I. *Perforaria Miill.-Arg. 



Apothecia with a wider opening ........................... 2. Pertusaria DC. 



Spores i-septate ................................................... 3. Varicellaria Nyl. 



XLV. LECANORACEAE 



Thallus mostly crustaceous, occasionally squamulose or very rarely 

 minutely fruticulose. The squamulose thallus is corticate above, the under 

 surface appressed and attached to the substratum by penetrating hyphae, 

 often effigurate at the circumference. Algal cells Protococcaceae. Apothecia 

 well distinguished by the thalline margin; spores colourless, simple or 

 variously septate or muriform. 



1 Bitter 



S. L. 22 



