Simmons, Remarks about tke Relation of the Floras etc. 
185 
Tlie genus Fucus itself however is represented in the arctic 
seas by 4 species, or by 11 if the disposition of De Toni (14, 
III, p. 193 — 209) is followed. Still more species are described but 
the later authors have reduced the number considerably. If the 
definition of species is followed, that Rosenvinge (42) has proposed 
(I have used it above) we have one widelv spread arctic species, 
F. infiaius , witli numerous varieties, fonnd also as well some way 
down in theAtlantic as in the Pacific. The other species reported 
from the latter ocean is perhaps not quite sure (as it is excluded by 
Set ch eil and Gardner (49) from the flora of north Western 
America). It is F. vesiculosus , the most common in the Atlantic, 
that although entering the Polar Sea is not extremely arctic. 
The two others, F. ceranoides and F. serratus are northatlantic 
species, that only enter the Spitzbergen district a little way 
north ward. Furt her we have one species, F. s piralis , in the 
northern Atlantic and one (2 or 3 ?) that goes down to Southern 
Europe (F. virsoides in the Mediterranean). It cannot be denied 
that there is a possibility to seek the tertiary origin of the 
genus as well in the Polar Sea as in the Atlantic, but I am 
more inclined to think, that it first entered the latter sea as a 
fugitive before the glaciation, eise it should have more repre- 
sentatives in the Atlantic. In the northern Pacific the Fucaceae 
are very scantily represented. S etc hell (49) has besides the 
abovementioned FWws-species only one Cystophyllum and with 
doubt a Cystoseira. Farther soutli in the Pacific many genera 
are represented, such as have a great distribution to the soutli 
in general. The Atlantic as previously mentioned has its own 
genera of Fucaceae, limited to the northern part. 
A still greater filterest attaches to the Laminariaceae. As 
pointed out especially by Setchell (48) the familyis distributed 
principally in two widely separated areas, one arctic and circum- 
polar in the northern seas, another circumpolar in the Southern 
hemisphere, including also the antarctic regions as far as the 
conditions there allow a Vegetation of higher algae to exist. 
There is however a very marked difference between these two 
areas of distribution, especially wlien the Arctic Sea and the 
northern Atlantic are compared with the Southern district, The 
former area is characterised by 6 genera, of which one only is 
(perhaps) represented within the Southern ränge of distribution. 
On the other hand the forms, that give the character to the 
Southern area are entirely absent from the abovementioned parts 
of the northern one, but are represented in the northern Pacific 
by allied genera and species or even by identic ones. 
Setchell (48) gives a table of distribution to which must 
be referred for particulars. Even if some new species are added 
since and the area for some has got additions, the differences 
are not so great as to make a new survey necessary, especially 
as the alterations do not apply to the genera to which the spe- 
cial filterest for this research attaches. In the above quoted 
treatise Setchell divides the Laminariaceae into three tribes: 
