270 DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 



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. Arctiv Greenland. — In area Arctic Greenland exceeds any other arctic district 

 except the Asiatic, Init 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, forming a 

 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, Avhich 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 Upernsevik 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 valleys along 

 the shore terminating in glacier-headed fiords, and the coast is bound by glaciers of prodi- 

 gious extent from Melville Bay northwards to Smith's Sound. 



The isothermal lines in Greenland all follow one course, from S.W. to N.E., running 

 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 6° through its north 

 extreme at Smith's Sound. The June isotherm of 41° skirts its east coast, and that of 

 32° passes north of Disco ; the June temperature of Disco is hence as low as that of the 

 north of Spitzbergen, of middle Nova Zembla, and of the extreme north of Asia, and 

 yet Disco contains quadruple their number of plants. The autumn cold is very great ; the 

 September isotherm of 32° crossing the arctic circle on the west coast ; and to this the 

 scantiness of the flora may to some extent be attributed. 



