222 ESSAYS. 



comparatively small area, not only most coniferous trees, but 

 a notably larger number of trees altogether than any other 

 part of the northern temperate zone ? Why should its only 

 and near rival be in the antipodes, namely, here in Atlantic 

 North America? In other words, why should the Pacific and 

 the European forests be so poor in comparison, and why the 

 Pacific poorest of all in deciduous, yet rich in coniferous 

 trees ? 



The first step toward an explanation of the superior rich- 

 ness in trees of these antipodal regions, is to note some strik- 

 ing similarities of the two, and especially the number of 

 peculiar types which' they divide between them. The ulti- 

 mate conclusion may at length be ventured, that this richness 

 is normal, and that what we really have to explain is the ab- 

 sence of so many forms from Europe on the one hand, from 

 Oregon and California on the other. Let me recall to mind 

 the list of kinds (i. e. genera) of trees which enrich our At- 

 lantic forest but are wanting to that of the Pacific. Now al- 

 most all these recur, in more or less similar but not identical 

 species, in Japan, north China, etc. Some of them are like- 

 wise European, but more are not so. Extending the com- 

 parison to shrubs and herbs, it more and more appears, that 

 the forms and types which we count as peculiar to our At- 

 lantic region, when we compare them, as we first naturally 

 do, with Europe and with our West, have their close counter- 

 parts in Japan and north China ; some in identical species 

 (especially among the herbs), often in strikingly similar 

 ones, not rarely as sole species of peculiar genera or in related 

 generic types. I was a very young botanist when I began to 

 notice this ; and I have from time to time made lists of such 

 instances. Evidences of this remarkable relationship have 

 multiplied year after year, until what was long a wonder has 

 come to be so common that I should now not be greatly sur- 

 prised if a Sarracenia or a Dionaea, or their like, should turn 

 up in eastern Asia. Very few of such isolated types remain 

 without counterparts. It is as if Nature, when she had 

 enough species of a genus to go round, dealt them fairly, one 

 at least to each quarter of our zone ; but when she had only 



