SEQUOIA AND ITS HISTORY. 161 
Very similar would seem to have been the fate of a more 
familiar gymnospermous tree, the Gingko or Salisburia. It 
is now indigenous to Japan only. Its ancestor, as we may 
fairly call it, — since, according to Heer, “it corresponds so 
entirely with the living species that it can scarcely be sepa- 
rated from it,” — once inhabited northern Europe and the 
whole arctic region round to Alaska, and had even a repre- 
sentative farther south, in our Rocky Mountain district. For 
some reason, this and Glyptostrobus survive only on the 
shores of eastern Asia. 
Libocedrus, on the other hand, appears to have cast in its 
lot with the Sequoias. Two species, according to Heer, were 
with them in Spitzbergen. L. decurrens, the Incense Cedar, 
is one of the noblest associates of the present Redwoods. 
But all the rest are in the southern hemisphere, two at the 
southern extremity of the Andes, two in the South Sea Is- 
lands. It is only by bold and far-reaching suppositions that 
they can be geographically associated. 
The genealogy of the Torreyas is still wholly obscure ; yet 
it is not unlikely that the Yew-like trees, named Taxites, which 
flourished with the Sequoias in the tertiary arctic forests, are 
the remote ancestors of the three species of Torreya, now 
severally in Florida, in California, and in Japan. 
As to the Pines and Firs, these were more numerously as- 
sociated with the ancient Sequoias of the polar forests than 
with their present representatives, but in different ‘species, 
apparently more like those of eastern than of western North 
America. They must have encircled the polar zone then, as 
they encircle the present temperate zone now. 
I must refrain from all enumeration of the angiospermous 
or ordinary deciduous trees and shrubs, which are now 
known, by their fossil remains, to have flourished throughout 
the polar regions when Greenland better deserved its name 
and enjoyed the present climate of New England and New 
Jersey. Then Greenland and the rest of the north abounded 
with Oaks, representing the several groups of species which 
now inhabit both our eastern and western forest districts ; 
several Poplars, one very like our Balsam Poplar, or Balm of 
