I92I. No. 7- STUDIES 0.\ THE LICHEN FLORA OF NORWAY. I7 



1. The Coast Flora. 



1. Lichens of the west coast. 



These lichens are essentiall}- southern. A foreigner would perhaps 

 search for them on our south coast, but on the contrary they are almost 

 exclusively western: distributed on the Atlantic coast from Lindesnes to 

 Stat (as tar as we know, the coast of More has been poorly investigated), 

 and not recorded from the fjords. 



This agrees well with phanerogams of a similar distribution. 



As type-plant we may choose Sfida Thoiiarsii but the group is not 

 small in the number of its species. There are further Sticta crocata, Sticta 

 limhata, Usnca fragilcscens, Parmclia laevigata, Parmelia trichbtera, Parynelia 

 iwcrcscens, Sphaerophonis iiielaiiocarpits, Ramaliua Ciirnotvii (?), and perhaps 

 Lichiiia pygiiiaea. The latter has been recorded from Anuglen (Du Rietz) 

 and from Bogøen (Sommerfelt). 



Their horizontal distribution is limited, and the same is still more the 

 case with their frequency, man}- of them are S-ery rare' in Norway. 

 It is, however, probable that the stations recorded will be augmented, for 

 large areas of Western Norway have not been sufficiently investigated. 



As long as we know so little of the conditions of life of the lichens, 

 it is of little use to speculate on the factors which limit their distribution. 

 But we may mention that they live at places where the winter temperature 

 is high, they avoid places with severe frost. And they prefer protected 

 stations, if not directly dependent on the surf. 



Their distribution suggests a southern maritime element with its northern- 

 most outpost on our west coast. 



Each and all of them are tound in the British Islands, and they are 

 more common there than in our country. Some of them, e. g. Sticta 

 I'rocata, have a world-wide distribution in exotic countries. 



But these plants which are so strictly maritime in Norway are not at all 

 maritime in southern countries, apart from a few species. Their distribu- 

 tion in Norway must, accordingly, be limited by more local factors, none 

 of which is more probable than the winter temperature. — When better 

 informed of their distribution it will be of great interest to compare it 

 Avith special isotherms. 



2. South coast lichens. 



These are coast plants of a wider distribution than the above mentioned. 

 Eastwards they reach the Swedish frontier. Northwards many of them 

 advance to Stat, but further investigation of the Mere coast will most 

 probably extend their known distribution. A few of them reach Saiten, 

 sheltered against Arctic climate by the Lofoten Islands. 



Vid.-Selsk. Skr. I. M.-N. Kl. 1921. No. 7. 2 



