A «urvey of the Phytogeography of the Arctic American Archipelago 135 
Witliin nn area stretching over 21'/2"> north and south, and 64° east and 
west, there must of course be very considerable floristic differeuces, a fact that is 
also to be seen from tlie lists of distribution in the preceeding flora. For the 
discussion of these, however, it becomes necessary to make up a sumniary of the 
distribution of the separate species, so as to facilitate their arrangement in geographic 
groups. For this purpose the following table (V) is put together. Tiie first six columns 
of the table account for tlie appearance of the species in question within each of the 
six natural groups into which I have divided the Archipelago (p. 23). A » + » in 
the column marks presence of the plant in question, but in some cases J have 
thought advisable to use other signs; so in the second column a »W» signifies that 
the plant is found hitherto only in King WilHam Land, »B» stånds for Boothia 
Fehx, »S» for North Somerset; in the third column »B» stånds for Baffin Land, 
»M» for the Mel ville Peninsula, and »H» for the islands in the northeni part of 
Hudson Bay; in the sixth column »E» stånds for Ellesmereland and »D» for North 
Devon. As the distribution outside the Archipelago is of an equal interest with 
that inside the area of the present research, columns are added for Greenland, 
America, and Eurasia also; in the ninth column »A» stånds for Asia, *E» for 
Europé. In the different columns »e» signifies eastern, »w» western, »n» northern, 
»s» Southern, »ne» northeastern, »nw» northwestern, »se» southeastern, »ne» north- 
eastern, »c» central, »a» arctic. 
As it seemed probable that the geological nature of the ground of the diffe- 
rent localities could be decisive for the appearance of some plants at least, another 
column is added where account is given of the rockground of different geological 
systems upon which each species is found. The abbreviations used here are the 
same as in the list of localities (p. 32). The wellknown difference between calci- 
philous and calciphobous plants was to be expected to appear also in our area, 
but actually it seems hardly to exist in the Arctic Islands; the larger part of the 
species in the flora are found as well on Archaean strata and on sandstones, slates, 
etc, as on limestone ground. There are, indeed, not few species found on rocks 
of a certain system alone, but in no case there is any necessity for assuming the 
kind of rock to be responsible for this circumstance, other explanations always 
being more satisfactory. We may therefore, I think, assume that every species in 
the flora can grow on any kind of rock bottom as far as the chemical nature of 
the soil is concerned, but some species more or less conspicuously pre f er certain 
rocks, or at least avoid some. As previously pointed out, this especially is the case 
with the Silurian limestones. 
The poverty of the vegetation of the Silurian districts, when compared with 
that of for instance the Archaean and Carboniferous ones, which has so often ira- 
pressed the travellers of older times, and which I have for my own part observed 
in Ellesmereland and adjacent islands, must, in my opinion, be explained as depen- 
ding on the manner of disintegration of the strata in question. The Silurian strata, 
building up most parts of the middle region of the Archipelago from the Continent 
