162 
Simmons, Eemarks aboufcthe Relations of the Floras etc. 
The species common to all the four arctic districts are very 
few, only 17 (19), giving 12 per ct. of the whole number, wliich 
seems to speak against the looking upon the present flora of the 
Polar Sea as old and directly descending from the former flora 
of the regions it now occupies. The 19 species under 1. (table 
III) are: 
*Pylaiella litoralis 
*Sphacelaria racemosa 
*Chaetopteris plumosa 
*Phloeosphora tortilis 
* Desmarestia aculeata 
*Llachista fucicola 
*Chordaria fl agelli fo nn is 
Laminaria cuneifolia 
„ solidungula 
*Fucus i n flatus 
Of these the species marked with * are found in the nor- 
thern part of the Atlantic as well as of the Pacific, and some of 
them are still wider distributed. Only Laminaria cuneifolia and 
L. solidungula do not go down into the Atlantic, but the former at 
least seems to have been found in the Pacific. Phyllophora in- 
terrupta is a decidedly arctic form, notwithstanding its being 
found also on atlantic coasts, where it is eise substituted by Ph. 
Brodiaei. However the above list will, as I have already allu- 
ded to, probably get considerable additions, when we get a bet- 
knowledge of the american and asiatic Polar Sea. Yet, even if 
all species not found only in one of the least explored districts, 
a number of about 20, were distributed, all over the arctic re- 
gions, we would still get only about 25 per ct. of the whole 
flora. Indeed, the groups, 6, 12, 13, containing the numbers of 
species from the best known districts show a total of 98 spe- 
cies, but it is very improbable that the majority of these will 
ever be found in the other regions. If some will, it surely must 
be some of the species that are common to the whole area north 
of the Atlantic, but it must be remembered, that it is not only 
through the better exploration, that Western Greenland and at 
least some parts of the Spitzbergen province show so much grea- 
ter figures than the other districts, but that also the natural 
conditions of those coasts play their part, and that the neigh- 
bourhood of atlantic, richly stocked districts has facilitated Im- 
migration of Southern forms. Thus I think it will always be 
necessary to uphold the assertion, that the present arctic ma- 
rine flora is no unity and that its origin can hardly be in the 
regions it now ocmrpies. I will give further reasons for this 
opinion later, but now the flora of the Spitzbergen district must 
be studied some what closer. The 120 species of that area are 
disti'ibuted as follows: 
Phyllophora interrupta 
* Luthora cristata 
* Rhodymenia palmata 
* Ralosaccion ramentaceum 
* Delesseria sinuosa 
* Polysiphonia arctica 
*Rliodomela lycopodioides 
*Ptilota pectinata 
* Antithamnion boreale. 
