76 



KJELLMAN, THE ALGiE OF TIIK AKCTIC SEA. 



in the northern part of the Atlantic, besides in the present glacial region, it is difficult 

 to form any decisive conclusion. It seems probable, liowever, that a considerable 

 number of these must or may be thought to have developed in the Arctic Sea and to 

 have migrated from there southwards. In any case, the number of those species of 

 the arctic marine Flora whose origin must be phiced within the Arctic Sea, cannot be 

 estimated at less than about 100 species, i. e. about 60 per cent of the total nuinber 

 of the species. 



In comparison with other northern Floras, the arctic Flora is proportionally poor 

 in Floridea', rich in Chlorophyllophycea?- and especially in Fucoidea^. This is shown by 

 the following list: 



Floridetc are, of tiic total iiuniber of the 

 species 



FucoideiB 



Chlovophyllophyceaj 



Tlie arctic 

 Flora. 



37 % 

 37 » 

 21 .. 



The Flora 



of the 

 Norwegiau 

 Polar Sea. 



41 % 

 35 » 

 21 .. 



The Flora of 

 Scandinavia. ') 



42 % 

 35 » 

 19 .. 



The Flora 

 of New- 

 England. 2) 



43 % 



25 " 

 18 » 



The Flora 

 of Great 

 Britain. ^) 



49 % 

 25 » 

 17 « 



The Flora at 

 Chcrhourg. ■*) 



46 % 

 28 " 

 13 »' 



Of the Nostochineai I shall not speak here, their inarine species being still too 

 little studied, and the determination of the species being more fluctuating in this group 

 of alga3 than in any other. Nearly a third part of the Fucoideas belongs to the same 

 family, the Laminariaceai, the richest in species of all the families of the arctic Flora, 

 with 20 species, amorjg wliich one Chorda. In the Scandinavian Flora this family pos- 

 sesses with certainty no more than 10 species, amongst which are three species of 

 Chorda, on the coasts of England only 7, at Cherbourg 5, including at the two last- 

 mentioned places one species of Chorda. On the north-eastern coast of America the 

 Laminariaceaä are more numerous. But it is impossible at present to state with cer- 

 tainty the number of their species there. However, it does not probably amount to 

 more than half of the arctic. 



The average number of species in the families is soraewdiat less in the arctic Flora 

 than in the Scandinavian. In the former there are about 5,i species in each family, in 

 the latter 6,i. However, the Scandinavian Flora contains comparatively more (38 %) 

 families with only a single species, than the arctic (26 %). Of the 34 families of the 

 arctic Flora 2 are monotypical, of the 47 families of the Scandinavian Flora only 3 



') Cp. Enum. Plant. Scand. 



^) Cp. Farlow, New-Engl. Alg. p. 184. 



^) Cp. Harvey, Phyo. Brit. 



*) Cp. Le JoLis, List. Alg. Cherb. 



') To these figures, of course, ouly a relative value cau be assigned, as I liave used the statemeuts giveu in 

 the works qnoted, without allowing for differences in the determination of species or the alterations suflered 

 by the figures exhibited, in consequence of new species having been added after the publication of the 

 works. But notwithstanding this, the proportion between the series in question is no doubt correotly ex- 

 pressed in the main by the figures given, as a reduction or addition may be supposed to have taken 

 plaoe in an equal degree with regard to all. 



