BANGE OF PLANTS 437 
centre and migrating to any extent from one focus of greater 
development. 
I do not think there is in the North any instance of the 
floras of two such remote spots as Kerg. Land and Cape 
Horn being identicaL Two Floras appear in the Northern 
Hemisphere, the American and the European. The former 
is confined to the American Arctic shores and islands, the 
latter to all Arctic Europe, Asia and Greenland : Western 
x^rctic American to the W. of the great chain of the Eocky 
Mountains, and North of the Oregon Piiver may also belong 
to the European Flora and is likely to, but I have not 
compared, having no materials in the Erebus. The abrupt 
Hne of demarkation is most remarkable in Baffin's Bay and 
Davis Straits, the most common European Heathers and 
some other plants being found abundantly along the Eastern 
shores and islands of those waters, but never on the Western. 
Of course a multitude of plants are common to both Hemi- 
spheres, which makes it in one sense the more remarkable 
that two or three of the types of Northern European Botany 
should not cross to the Westward of Longitude 60° W. 
I have been progressing with the Antarctic plants, using 
yours, King's and my own at once, and each according 
to the Nat. Ords., beginning with Eanunculaceae, where 
the value of every scrap tells better than it is possible to 
suppose. The little Cardamine or Cress I prove, by com- 
parison with about 50 states of it running through the whole 
continent of S. America, to be the same as the most common 
European weed, C. Jiirsuta. This is not wonderful, but it 
is, that Winter's Bark, Drimijs Winteri, should extend 
through the whole continent of S. America and Mexico, from 
25° N. to 56° S. It is true that the extreme states vary, 
and apparently specifically, but take the regular series of 
specimens, beginning with my own Cape Horn ones, your 
and King's Fuegian, Bertero's and Bridge's and Cuming's 
Chilian, the Brazilian ones of many collectors ; Peruvian 
and Bolivian States from others ; and finally, end the list 
with the Mexican, and no one (not even the most determined 
species-monger) can make them specifically distinct. It 
is further proved by the later Brazilian Botanical authors 
considering their Species the Chilian, and contemporaneous 
Mexican writers, not aware of this last re-union, uniting 
VOL. I 2 F 
