OTTO V. DARBISHIRE. [SEC. ARCT. EXP. FRAM 



I think I am correct in saying that land which is free of ice or 

 snow atleast for the greater portion of the year will produce lichens. 

 It is necessary ofcourse also that the substratum should not he a mov- 

 ing one. Sand or shifting stones or earth would never bear a lichen- 

 vegetation. But the exposed nunataks and earth will bolh ultimately 

 be covered by lichens. These are the two most important substrata in 

 the district under consideration. Tree-lichens are ofcourse absent. 



I am not able here to say exactly why the bare earth in some cases 

 is covered with moss and in some cases with lichens. But it is prob- 

 ably a question of water-supply, or rather rapidity of evaporation. At 

 any rate it ultimately depends on the power of the particular plant to 

 stand drought. From my own observations in this country I know that 

 on the open hillside the lichens occupy the drier localities. They form 

 in fact the outskirts of vegetation, though they naturally occur mixed 

 with mosses in many localities. Not only are lichens satisfied with less 

 water but they can absorb the smallest quantity with the greatest avi- 

 dity They can also without apparently taking any harm dry up till they 

 become quite brittle. In this condition they are able to withstand the 

 greatest cold without being injured. We thus find them in the most 

 exposed positions on the bare faces of rocks, where no moss could find 

 a firm hold. 



As far as the exposed earth is concerned the lichens we find will 

 depend largely on the time which the locality has been undisturbed, for 

 lichens grow very slowly. 



Not a few of the bigger species found on the bare earth may also 

 be found among moss or even growing over it. To this class belong 

 plants like Stereocaulon alpinum, paschale and Cladonia pyxidata. 

 In the same way Physcia pulverulenta and muscigena, which is per- 

 haps hardly a separate species, grow abundantly in and over moss. 

 Dactylina arctica and Thamnolia vermicularis both occur amongst moss 

 but the latter very often passes beyond the moss-area. It has even been 

 found firmly attached to some droppings of the musk-ox (North Lincoln : 

 Framfjord). Dufourea muricata here and there found among moss 

 generally occurs in pure formations. In this it is followed by most of 

 the species of Cetraria. We thus get quite extensive beds of Cetraria 

 cucullata, hiascens, nivalis and to a smaller degree apparently islan- 

 diea. Alectoria nigricans and ochroleuca though often found in pure 

 formations are more common, so it would appear, in close company 

 with mosses. The different species of Peltigera are well represented in 

 the area under consideration. They are known to favour moist places 



