CONTENTS xi 



3. SOREDIA 



PACK 



A. STRUCTURE AND ORIGIN OF SOREDIA . . . 141 



a. Scattered soredia 



b. Isidial soredia 



c. Soredia as buds 



B. SORALIA ..'..-.-.. . 144 



a. Form and occurrence of soralia 



b. Position of soraliferous lobes 



c. Deep-seated soralia 



C. DISPERSAL AND GERMINATION OF SOREDIA . . 147 



D. EVOLUTION OF SOREDIA . ... 148 



4. ISIDIA 



A. FORM AND STRUCTURE OF ISIDIA . . . 149 



B. ORIGIN AND FUNCTION OF ISIDIA . . . .151 



VI. HYMENOLICHENS 



A. AFFINITY WITH OTHER PLANTS . .152 



B. STRUCTURE OF THALLUS . . . . .153 



C. SPORIFEROUS TISSUES 154 



CHAPTER IV 



REPRODUCTION 



I. REPRODUCTION BY ASCOSPORES 



A. HISTORICAL SURVEY 155 



B FORMS OF REPRODUCTIVE ORGANS . . . .156 



a. Apothecia 



b. Perithecia 



C. DEVELOPMENT OF REPRODUCTIVE ORGANS . . 159 



i. DISCOLICHENS 



a. Carpogonia of gelatinous lichens . 



b. Carpogonia of non-gelatinous lichens 



c. General summary 



d. Hypothecium and paraphyses 



e. Variations in apothecial development 



aa. Parmeliae 

 bb. Pertusariae 

 cc. Graphideae 

 dd. Cladoniae 



