PREFACE. 



i he first scientist to investigate systematically the Norwegian lichen 

 flora was Johan Ernst Gunnerus, Bishop of Trondhjem (Drontheim), more 

 than 150 years ago. 



Since then man\- botanists have worked at this important part of our 

 flora. It is of great interest to follow their investigations, but it mav be 

 better to reserve the results of my studies on this matter for a special 

 publication. 



We now know something regarding the distribution of the lichens in 

 our country, but there is still an enormous amount of work to be done. 



Many provinces have been more or less thoroughlv explored, but 

 from a modern point of view large provinces must still be regarded as 

 almost virgin land. 



The nearest vicinity of Kristiania has been investigated by many 

 lichenologists, where the most important work has been carried out by 

 N. G. MoE. But the adjacent districts in all directions are still insufficiently 

 known, for little systematic work of real value has been done there since 

 the days of M. N. Blytt, S. C. Sommerfelt, and N. G. Moe. 



Osterdalen has a poor lichen flora, the northernmost part being the 

 richest, and this has also been explored to a certain degree. Many bota- 

 nists have stopped in Gudbrandsdalen for some time on their way to Dovre, 

 and S. C. Sommerfelt had his residence in Ringebu for several years. 

 Hardly any district has been so well investigated by many botanists as 

 the Dovre mountain, famous for its rich flora. M. N. Blytt paid great 

 attention to \'alders where the lichen flora is rich, and has much in com- 

 mon with that of Gudbrandsdalen. But after him no lichenologist has been 

 there. We have few lichens from Hallingdal, Fr. Kler collected lichens 

 in Numedal and also in \'estfjorddalen, but he was more interested in 

 mosses than in lichens. 



There is a great gap in our knowledge, ranging from Telemarken to 

 the Stavanger district. We have only some collections from Gausta, and 

 from a few places on the coast. 



Western Norway has had the advantage of being explored in recent 

 years by an eminent observer, J. J. Havaas. Raegefjord and Moster on 



