CONTENTS. 



Preface 

 Introduction 



PART I. 

 The General Consideration of Lichens. 



SECTION I. 



The History of Lichenology 1 



I. From the Earliest Time to Wallroth and 



Meyer (1825) 2 



II. From Wallroth and Meyer (1825) to the Close 



of 1896 8 



SECTION II. 



The Uses of Lichens 16 



I. The Function of Lichens in Nature ... 17 



II. The Economic Value of Lichens .... 18 



SECTION III. 



What are Lichens? 25 



I. The Origin of a Lichen 29 



II. The Relation of the Lichens to Algjs and 



Fungi 33 



in. Lichens as Morphological Units .... 36 



57G1.' 



•^ 



