7i-2 ( iTTO V. DARBISHIRE. [SEC. ARr.T. EXP. FRAM 



lower (luxvii. taken Germany and the Tirol as objects for comparison. 

 T" tin.- matter I will refer directly. 



i )n a luniiei- occasion, in discussing the lichen-flora of Greenland. 

 I (minted nut the remarkable likeness of the flora of Greenland to that 

 of Germany. Of ^SG lichens recorded for Greenland up to that date, 

 namely |S'.)7. 1.MM occnred in Germanv. Of these 

 105 or i'.. I o ^"ere (tnrely alpine. 

 11 or .".) - preferred alpine situations, 

 '.17 or \'\ were common to the hill and the plain. 



That i- to say of the Greenland species found in Germany 54.5",, 

 \\ere found to he mainly alpine, hut all ((radically had been recorded 

 from the hills. Another point of interest was referred to in the (taper 

 on Greenland lichens. Of the 171 crnstaceons lichens recorded from 

 Greenland 1 10 or C4.. % 1 " ,, were recorded from Germany, of the foliace- 

 on- lichen- DO or S5.7" , and of the fruticnlose lichens 34 or 94.4",,. 



These figures were explained by reference to the advance and the 

 linal retreat of the ice after the last ice-age. During the greatest ex- 

 t-Mi-ion of the ice in the ice-age the lichens would be pushed well to the 

 -i mlli and into the plains. When the ice retreated however they would 

 pa-- up to the north and into the hills, into the colder zones and 

 regions. The warmer strips of land intervening would then separate 

 the alpine and the northern lichen-floras. 



The oldest forms, the fruticnlose lichens, would go back to the time- 

 when the alpine and northern floras were still united. We find there- 

 fore thai '.''(. 1 " ,, of the Greenland fruticulose lichens are found in Ger- 

 many, of which houever not a few are found in the plains. Of the less 

 highly differentiated crustaceous lichens which must be considered to be 

 of limn- recent development only C>i.'! " ,, are common to Germany and 

 Greenland. I would like to -ay that I consider it not unlikely that a 

 number of Ihe-e cin.-laceoiis species are really species alike in their e\- 

 I'-rnal morphology only and that they are not really related to one 

 another otherwise. We mav call a Greenland plant by the same name 

 a> the German one. and a- far as we are able to judge \\e may be 

 I -tilled 111 so doniL:. At the some time lhr two plants may have been 

 -.-paralrly derived though from some common ancestor. Some of the 

 higher fruticulose >prcir- -enn never to vary, whereas the variation- 

 among the simpler crustaceous species are at the best most pn/./.ling and 



of lle<|llelll occurrence. 



Tin- folloum- table- are ha-ed on the list of '!:> lichens enumerated 

 above. They confirm the views already expressed: 



