150 ESSAYS. 
ern China, — belongs, therefore, to the eastern Asiatic tem- 
perate region, of which northern China is a part, and Japan, 
as we shall see, the portion most interesting to us. There is 
only one more species of Torreya, and that is a companion of 
the Redwoods in California. It is the tree locally known 
under the name of the California Nutmeg. Here are three 
or four near brethren, species of the same genus, known no- 
where else than in these three habitats. 
Moreover, the Torreya of Florida is associated with a Yew; 
and the trees of this grove are the only Yew-trees of eastern 
North America; for the Yew of our northern woods is a de- 
cumbent shrub. A Yew-tree, perhaps the same, is found with 
Taxodium in the temperate parts of Mexico. The only other 
Yews in America grow with the Redwoods and the other 
Torreya in California, and extend northward into Oregon. 
Yews are also associated with Torreya in Japan; and they 
extend westward through Mandchuria and the Himalayas to 
western Europe, and even to the Azores Islands, where occurs’ 
the common Yew of the Old World. 
So we have three groups of coniferous trees which agree in 
this peculiar geographical distribution, with, however, a nota- 
ble extension of range in the case of the Yew: first, the Red- 
woods, and their relatives, Taxodium and Glyptostrobus, which 
differ so as to constitute a genus for each of the three regions ; 
second, the Torreyas, more nearly akin, merely a different 
species in each region; third, the Yews, still more closely re- 
lated while more widely disseminated, of which it is yet un- 
certain whether they constitute seven, five, three, or only one 
species. Opinions differ, and can hardly be brought to any 
decisive test. However it be determined, it may still be said 
that the extreme differences among the Yews do not surpass 
those of the recognized variations of the European Yew, the 
cultivated races included. 
It appears to me that these several instances all raise the 
very same question, only with different degrees of emphasis, 
and, if to be explained at all, will have the same kind of ex- 
planation. 
Continuing the comparison between the three regions with 
