270 DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 
o 
essay the information gleaned from all of them. For the southern distribution of these 
plants in the United States, &c, I have had recourse primarily to Asa Gray's excellent 
' Manual of the Botany of the Northern United States,' to Chapman's ■ Flora of the S.E. 
States,' and to the reports on the Botany of various Exploring Expeditions. 
5. Arctic Greenland. — In area Arctic Greenland exceeds any other arctic district 
except the Asiatic, but ranks lowest of all in number of contained species. In many 
respects it is the most remarkable of all the provinces, containing no peculiar species 
whatever, scarcely any peculiarly American ones, and but a scanty selection of European. 
A further peculiarity is that the flora of its temperate regions is extremely poor, and adds 
very few species to the whole flora, and, with few exceptions, only such as are arctic in 
Europe also. Being the only arctic land that contracts to the southward, formi ^ 
peninsula, which terminates in the ocean in a high northern latitude, Greenland offers 
the key to the explanation of most of the phenomena of arctic vegetation ; and as I have 
already made use of it for this purpose, I shall be more full in my description of its flora 
than of any other. 
The east and west coasts of Greenland differ in many important features ; the eastern 
is the largest in extent, the least indented by deep bays, is perennially encumbered 
throughout its entire length by icefields and bergs, which are carried south by a branch 
of the arctic current that sets between Iceland and Greenland ; and is hence excessively 
cold, barren, and almost inaccessible. The west coast, again, is generally more or less free 
from pack ice from Cape Farewell (lat. 60°) to north of Upernamk in lat. 73°. It is 
washed by a southerly current, which is said to carry drift timber from the Siberian rivers 
into its fiords, and enjoys a far milder climate, and consequently has a more luxuriant 
vegetation. A somewhat similar contrast is exhibited between West Greenland and the 
opposite shores of Baffin's Bay, against which latter the northerly arctic current from 
Lancaster Sound drives great masses of polar ice, derived from the regions beyond that 
estuary, and to which the bergs that float away from the glaciers in the Greenland fiords 
are also drifted. It is important to bear in mind these features of the two shores of 
Greenland and of Baffin's Bay and Davis' Straits, because they may in some degree 
explain their differences of vegetation. There is also another difference between the polar 
islands and Greenland, inasmuch as the former are for the most part low, without moun- 
tains or extensive glaciers ; while the latter is exceedingly mountainous, with valley. , 
the shore terminating iu glacier-headed fiords, and the coast is bound by glaciers of prodi 
gious extent from Melville Bay northwards to Smith's Sound. 
The isothermal Hues in Greenland all follow one course, from S.W. to N.E.. runnin 
5 
more 
parallel to one another in this meridian than in any other. The isotherm of 32 
passes through the southern extremity of the peninsula, and that of 5° through its north 
extreme at Smrth's Sound. The June isotherm of 41° skirts its east eoast, and that of 
32 passes .north of Diseo ; the June temperature of Disco is heuee as low as that of the 
north of Spitsbergen, of middle Nora Zembla, and of the extreme north of Asia, and 
> et Daseo contains quadruple their number of plants. The autumn eold is very great ; the 
September isotherm of °"° * " J 
of the flora may to some extent be attributed 
circle on the west coast : and to this 
