l8 BERNT LVNGK. M.-X. Kl. 



They arc not specially western. The more southwards wc go the 

 greater their miiiihei", and the more coiniiion Ukv hecome. 



The tvpc plant is Cladouia uiacrophyllodrs, one of our largest Clado- 

 niae, with pulvinate squamules. Several other lichens of this group have 

 the same pulvinate form, e. g. Cladouia strcpsilis. A pul\ inate habitus is 

 common on the coast. It offers protection against the influence of the wind. 



Other species are Cladouia alcicornis, Parmelia scortea, Parmelia 

 Mougcotii, Stcreocaiilou cvoliituni, and as far as we can see Stereocaulon 

 coralloides var. congloinrrntiini. I'\irlhermore Cyrophora cirrliosa and Cla- 

 douia raiigiforinis which has the widest distributif)n of them all (to Saiten). 



We must not confuse these 'coast" lichens with strand lichens. 

 Several of them are found also in inland provinces, even at subalpine 

 stations, but they are much more common on the coast. Coast, subalpine 

 and lower alpine rocks have much in common. 



It is to be expected that the 'coast' lichens have their distribudon chiefl}- 

 southwards. But in southern countries there is hardl}' one of them which 

 is strictly maritime. This indicates that even their distribution in Norway 

 is limited by more local factors, most probably by the winter temperature, 

 just as is the case with the west coast lichens. 



It is impossible to attribute much importance to rainfall. Lichens 

 easily absorb moisture, but in general they have little power of retaining 

 it. After rain one hour of sunshine and wind is sufficient to dry up the 

 Cladiiiac, whilst Cetraria islandica on the other hand retains its moisture 

 better. A regular dew is, accordingly, of the same value as a rainfall, and 

 the dew is more contingent upon rapid changes in temperature than upon 

 the rainfall. 



We may here mention a plant which is otherwise difficult of classifica- 

 tion, e. g. Umbilicaria pushilata. It is plentiful along the strand on the 

 south coast and common on the western coast, lacking in continental low- 

 lands, but not rare or in places common on prominent subalpine or lower 

 alpine rocks. The same is the case with Gyrophora polyrrhiza and 

 G. crustulosa. Birds like to rest on such rocks, and these lichens are 

 supposed to be nitrophilous. 



The two groups mentioned are the most maritime ones among the 'coast 

 lichens'. 



3. Southern lowland lichens. 



Other lichens are almost as common in the continental lowlands as 

 on the coast itself. 



A group comprising plants of this distribution must.be rather hetero- 

 geneous. They are not well separated from the maritime species and on 

 the other hand they are found associated with more subalpine plants. 

 Only a thorough knowledge of their distribution at home and abroad and 



