H 



BERNT LYNGF:. 



M.-X. Kl. 



Other <oiiiiii()ii lichens af^^'li^ are projj.-ijrated by fragments of the 

 thallus, as many pendulous 'Ijcard lichens'. Apothecia are extremely rare 

 in ail Olli- species of / snrn, with the exce-ptir)n of ('sura florida, and also 

 in i ladtiiiia alpcstiis, the reindeer-moss. 



Accordingly we must admit that either of these manners of propaga- 

 tion is fully effective, but we cannot maintain that r>ne of them is the 

 most effective. 



We must suppose that even small fragments of a growing part of a 

 lichen thallus are sufficient to propagate the ]ilant if |>laced in favourable 



Fig. 5. Horse pulling two sledges loaded with Cladonta nlpcstns. 

 Sæteren in Haadalen between Roros and Fæmunden. iSortrondelag, near 

 Nordre Østerdalen.) Phot. K. Nissen 20. 3. 1916. 



conditions. Considering the power of the wind as a distributing spreading 

 agent, we may say that there is hardly any part of our country which 

 could not have been reached by lichen fragments capable of propagation. 

 Every year the wind carries leaves from Hardanger over the mountains to 

 Voss (Lid), and leaves have also been found on the top of the Hardanger 

 glacier (Hardangerjekelen) (Nordhagen), and leaves are heavy as compared 

 with small fragments of lichen: The wind distribution of soredia can be 

 compared with the distribution by wind of pollen grains. 



And yet the relative number of really ubiquitous lichens in A'orivay is 

 remarkably small. The relative number of phanerogams is much greater. 



Several causes are worthy of consideration. 



Owing to their slow rate of growth, lichens can only with difficulty 

 sustain themselves on spots fit for other plants. This considerably reduces 

 the available area for lichens. 



