CHAPTER IV. 

 The Growth, Mechanics and Chemistry of Lichens. 

 Introduction . . II. Growth of the Apothecia 75 



I. The Growth of the Thallus. 71 III. The Development and Struc- 

 i. The Protothallus (Hypothal- tore of the Spores 77 



lus, Promycelium) 71 IV. Growth of the Algae . . 78 



2. Development of the Thallus. 72 V. The Spermagonia So 



(a) Horizontal Growth. VI. MECHANICAL ADAPTATIONS . . 81 



(4) Vertical Growth. VII. The CHEMISTRY OF Li CHENS 84 



(c) Intercalary Growth. 



CHAPTER V. 



Reproduction and Propagation of Lichens. 



I. The Spores 87 II. The Soredia as Propagative 



1. The Ejection and Distribu- Organs . . 92 

 tion of Spores . . . . 87 III. Vegetative Propagation . 93 



2. The Germination of Spores 89 IV. Life-period of Lichens 94 



3. Spores as Organs of Repro- 

 duction . . 90 



CHAPTER VI. 

 The Polyphylogeny of Lichens. 

 Introduction . . . . 



I. The Fungal Types . . 



1. The Pezizaceae . . 



2. The Patellariaceae . 



3. The Phacidiaceae . 



4. The Stictidaceae 



5. The Sphaeriaceae 

 II. The Algal Types. . . 



1. Cystococcus humicola 



PART II. 

 The Clasification and Special Morphology of Lichens. 



CHAPTER I. 

 A System of Classification. 

 I. Introductory Considerations. 102 II. Chemical Reactions 106 



CHAPTER II. 



Descriptions of the Families and Genera. 



Introduction. ... . . . . 108 



General Description of the 



Plates . .110 



Key to the Families . 109 



I. Caliciaceae . . no II. 



1. Mycocalicium ... .112 



2. Coniocybe ... . .112 



