Sinimo 11s. Eemarks about the Relations of tbe Floras etc. 
175 
nooks of fjords and bays, but sucli localities are also most apt 
to hold their icesheat even in summertime. Düring the iceage 
a breaking up of the ice in such places can hardly have occu- 
red regularly, and consequently they can not have housed any 
considerable Vegetation. I will not go so far as to assert, that 
there can have been no Vegetation at all in the Polar Sea pro- 
per during the iceage, still I can come to no other conclusion 
but that it must have been a very scanty one; all littoral spe- 
cies were necessarily driven away or exstirpated, and of the 
sublittoral only a very limited number can have survived in some 
comparatively favorable localities. Among species that I am es- 
pecially inclined to reckon as such possible survivors are Phyl- 
Jophora interrupta , found even on the upploughed mudbottom 
in front of smaller glaciers, and the widely spread arctic Lami- 
naria solidungula. Some other common arctic species perhaps 
also could come into consideration, but I think it rather unpro- 
fitable to speculate upon this question, as the present distribu- 
tion can be as easily accounted for in another way. Of course 
those species, who were most able to stand the arctic conditions, 
were only driven a shorter way southwards than others and they 
followed the melting ice closely on their way back. Therefore 
they came first into the Polar Sea again and took possession of 
most parts of it. Doubtless this took place as well from the 
atlantic side as, perhaps in a smaller degree, also from the pa- 
cific. If the species in question were able to hold their ground 
against the new immigration of Southern forms, they also stayed 
as citizens of the now again warmer regions, where they had 
outlived the glacial period. Especially this has been the case 
where the nature still affords conditions of life somewhat simi- 
lar to those of the arctic regions, or where immigration from the 
south was difficult because the way southwards was early bro- 
ken for instance at the coast from Labrador down and in Ice- 
land. It must be remembered, that there has been a long time 
for these migrations, which are doubtless still in progress along 
the coasts as far as hydrographic and other conditions allow. 
That the currents do not exercise such an influence upon the 
Vegetation, as attributed to them especially by Agardh, clearly 
appears from the fact, that nothwithstanding the stream that 
sets in from the Bering Sea, there is only a very small number 
of pacific species that has come into the Polar Sea by way of 
Bering Strait, and that not a single representative of the many 
peculiar pacific genera, especially the numerous Laminar taceae, 
has entered here although some of them grow far north as well 
on the asiatic as on the american side. On the other hand a 
current can greatly influence the Vegetation of a coast by alte- 
ring the climate and other conditions of life, as is clearly shown 
by the arctic features of the Vegetation on the northern atlan- 
tic coast of America and by the almost purely atlantic flora 
along the coast of northern Norway. Of course I consider the 
Gulfstream as a factor of the greatest importance for the phy- 
