xvi CONTENTS 



PAGE 



D. EVOLUTION OF ARCHILICHENS .... . 287 



a. Thallus of Pyrenocarpineae 



b. Thallus of Coniocarpineae 



c. Thallus of Graphidineae 



d. Thallus of Cyclocarpineae 



AA. LECIDEALES 



aa. COENOGONIACEAE 



bb. LECIDEACEAE AND GYROPHORACEAE 



CC. Cl.ADONIACEAE 



1. Origin of Cladonia 



2. Evolution of the primary thallus 



3. Evolution of the secondary thallus 



4. Course of podetial development 



5. Variation in Cladonia 



6. Causes of variation 



7. Podetial development and spore-dissemination 



8. Pilophorus, Stereocaulon and Argopsis 

 BB. LECANORALES 



aa. COURSE OF DEVELOPMENT 

 bb. LECANORACEAE 

 ff. PARMEI.IACEAE 



dd. USNKACEAE 



ee. PHYSCIACEAE 



CHAPTER VIII 



SYSTEMATIC 

 I. CLASSIFICATION 



A. WORK OF SUCCESSIVE SYSTEMATISTS . . . 304 



a. Dillenius and Linnaeus. 



b. Acharius 



c. Schaerer 



d. Massalongo and Koerber 



e. Nylander 



f. Miiller-Argau 



g. Reinke 



h. Zahlbruckner 



B. FAMILIES AND GENERA OF ASCOLICHENS . . 311 

 C HYMENOLICHENS . 342 



II. NUMBER AND DISTRIBUTION 



I. ESTIMATES OF NUMBER 

 2. GEOGRAPHICAL DISTRIBUTION 



A. GENERAL SURVEY . . . . . . . 343 



B. LICHENS OF POLAR REGIONS . '/ . . . . 345 



C. LICHENS OF THE TEMPERATE ZONES . . . 348. 



D. LICHENS OF TROPICAL REGIONS .... 352 



III. FOSSIL LICHENS 



