A 8urvey of the Phytogeography of the Arctic American Archipelago 14Ö 
NW Greenl. an<i shall come back to again, reached it över the Arctic Archipelago 
and spread southwards, and final ly a considerable namber of european as well as 
of annerican species, confined to the southern part. How these have arrived there 
is the most difficult point to settle in the history of the Greenland flora, if the 
couvenient theory of »naturahsation a grande distance» is not unobjectionally adopted. 
In the case of the Arctic Archipelago there is no need of having recourse to 
such hazardous speculations, as there exists a practically unbroken överland way of 
migration from the Continent to the far north. How far the geoiogical evidence 
goes to affirm the assumption of the Archipelago as devoid of vegetation during 
the culmination of the iceage, we shall see låter on, that the composition of the 
present flora speaks in favour of it, may be granted I think. But in assuming the 
whole flora, or the main of it at least, as arrived there in postglacial ti me, the 
means of immigration are to be looked for which it can have used. 
Means of migration. The factors of dispersion generally reckoned with are: 
drift m water or on ice, wiud, animals, especially birds, and man. Turniug to 
the first of these, we may leave freshwater drift entirely out of cousideration, as 
it can only help to extend the raiige of a plant within a land where it is 
already introduced by other means. The drift in salt water ought in the first hne 
to be of importance in the case of halophytes. Very few plauts, however, in arctic 
floras are pronouncedly halophilous, and in that of the Archipelago they do not 
amount to more than seven, viz., Atropis maritima, Elymus arenarius and E. mollis, 
Carex salina, Stellaria humifiisa, Honhenya peploiåes, and Mertetisia maritima. As 
faciiltative halophytes may be counted: Atropis distans, Catabrosa algida, Cerastium 
alpinum, Cochlearia officinalis, Hippuris vulgaris, Polemonium horeale, and Matricarm 
inodora, but it must be reniembered that in the Arctic Regions these decidedly 
prefer inland localities to the shore. Some few more may occasionally be found 
on the seashore, but on the other hand a species such Statice maritima, a marked 
halophyte in the southern parts of its area, becomes an inland and mountaiu plant 
to the north, and Banunculus htjperhoreus, often found in brackwater in Danish 
Greenland, avoids the seashore in the Arctic Islands. Of the seven firstnamed 
species five are only found in the southern Islands, and likewise three of the next 
seven, so as to leave only six more or less halophilous plants in the flora of the 
northern islands. The halophytic element in the flora decidedly is very insignificant, 
and does not speak for attributing to the marine drift any large share in te stocking 
of the Archipelago. 
Some authors, however, have attributed a very great importance to marine 
currents as conveyances not only of halophytic plants, but of whole floras. Espe- 
cially has Gkisebach, Veg. d. Erde, I, p. 57 — 67, made the Polar Current respon- 
sible for the import of nearly all plants of Greenland from Siberia, and in låter 
time Sernandee, Spridningsl)iol., has tried to forward arguments for migration of 
plants over wide expanses of sea in the same manner. Buchenau and Focke in 
