PREFACE. 



This little work is especially written and arranged for the 

 use of amateurs in the study of lichens. By this it is not in- 

 tended to convey the idea that the presentation of the subject- 

 matter is unscientific, incorrect or even out of date. The 

 treatment of the subject is in harmony with the most recent 

 results obtained by tlie leaders in the study of lichenology ; I 

 have simply endeavored to present these results in such a way 

 that they may be comprehended by all ; in other words, an at- 

 tempt has been made to popularize our present knowledge of 

 lichens. It should, however, be kept clearly in mind that 

 only the known facts or the completed work of science can be 

 popularized. The advance-work of science, that is, the work 

 whose aim it is to make 7}ew discoveries or to correct errors, can 

 never he popularized ; as soon as this is attempted it ceases to 

 be advance-work. This statement is intended for those of the 

 laity who are inclined to speak of scientific work as " non- 

 sense " or as " a morbid taste for using big words." It is also 

 intended for the serious consideration of those would-be scien- 

 tists who are too anxious to "popularize science." It is 

 further hoped that this statement will avoid possible erro- 

 neous conclusions as to the intended purpose of this book. 



The existing nomenclature-difiiculty does not concern or 

 interest the average student of nature. In fact, the leading 

 scientific specialists are themselves as yet wholly at sea as to 

 when and where the controversy will end. For this reason 

 the citation of authorities is omitted. Tlie names given are 

 well authenticated, so that those who have the desire and the 



