4 <)TT< V. DAKBISHIHE. [SEC. ARCT. EXP. FRAM 



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



* 



snow a I least for the greater portion of the year \vill produce lichens. 

 It is necessary ofcoiir-e also that the substratum should not lit- a mov- 

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



lation. But the exposed nunalaks and earth will holh ultimately 

 he covered by lichens. These are the two most important suhstrata in 

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



I am not aide here to say exactly why the hare earth in some cases 

 is co\ered 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 will) less 

 \\ater 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 Stereocanlott <tli>'uinin. pascltalc and ('Iddoaid pif.cidata. 

 In the same way Plu/scia pulverulenta and muscigena, which is per- 

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

 1 >(icl illinn urctica and Tliamnolia vermicnlaris both occur amongst moss 

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

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

 1'Vamfjord). Itufimn'ii ntnriciilit here and there found among moss 

 ^i-nerally occurs in pure formations. In this it is followed by most of 

 the s|,,-cies df Cclrd riii. \Ve thus get quite extensive beds of Cctraria 

 <-n<-nHnffi. Itinxm/s. >/iru!ix and to a smaller degree apparently islan- 

 ilirn. .1/rr/o/m ii it/fic'iiis and ochroh'iu'd though often found in pure 

 formation-* are more common, so it would appear, in close company 

 with mosses. The different species of l'rlt/t/t'r<t are well represented in 

 tli-' area nndi-r consideration. Thev are known to favour moist places 



