CHAPTER I 



HISTORY OF LICHENOLOGY 



A. Introductory 



The term "lichen'' is a word of Greek origin used by Theophrastus in his 

 History of Plants to signify a superficial growth on the bark of olive-trees. 

 The name was given in the early days of botanical study not to lichens, as 

 we understand them, but to hepatics of the Marchantia type. Lichens 

 themselves were generally described along with various other somewhat 

 similar plants as "Muscus" (Moss) by the older writers, and more definitely 

 as "Musco-fungus" by Morison^ In a botanical work published in 1700 by 

 Tournefort^ all the members of the vegetable kingdom then known were 

 for the first time classified in genera, and the genus Lichen was reserved for 

 the plants that have been so designated since that time, though Dillenius' 

 in his works preferred the adjectival name Lichenoides. 



A painstaking historical account of lichens up to the beginning of 

 modern lichenology has been written by Krempelhuber'', a German licheno- 

 logist. He has grouped the data compiled by him into a series of Periods, 

 each one marked by some great advance in knowledge of the subject, 

 though, as we shall see, the advance from period to period has been con- 

 tinuous and gradual. While following generally on the lines laid down by 

 Krempelhuber, it will be possible to cite only the more prominent writers 

 and it will be of much interest to British readers to note especially the work 

 of our own botanists. 



Krempelhuber's periods are as follows: 



I. From the earliest times to the end of the seventeenth century. 

 II. Dating from the arrangement of plants into classes called genera 

 by Tournefort in 1694 to 1729. 



III. From Micheli's division of lichens into different orders in 1729 

 to 1780. 



IV. The definite and reasoned establishment of lichen genera based 

 on the structure of thallus and fruit by Weber in 1780 to 1803. 



V. The arrangement of all known lichens under their respective 

 genera by Acharius in 1803 to 1846. 

 VI. The recognition of spore characters in classification by De 

 Notaris in 1846 to 1867. 



' Morison 1699. ^ Tournefort 1694 and 1700. ' Dillenius 1741. ■* Krempelhuber i867-i87'2. 

 S. L. I 



