72 BULLETIN QNITBD STATES GEOLOGICALSURVEY. [Vol.VT. 



And why should tin- Northeast Asian region have, in a comparatively small area, not 

 only most coniferous trees, bul a ootably larger number of trees altogether than any 

 other part of the northern temperate zone I Why should its only and near rival he 

 in the antipodes, namely, here in Atlantic North America f In other words, why should 

 tin Pacific ami the European forests he so poor in comparison, and why the Pacific 

 poorest of all in deciduous yd rich in coniferous trees ? 



The first step toward an explanation of the superior richness in trees of these an- 

 tipodal regions, is to note some striking similarities of the two, and especially the 

 number of peculiar types which they divide between them. The ultimate conclusion 

 may at length be ventured, thai this richness is normal, and that what we really have 

 to explain is the absence 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 Atlantic forest but are wanting to that of the Pacific. Now 

 almost all these recur, in more or less similar but not identical species, in Japan, North 

 China, &c. Some of them are likewise European, but more are not so. Extending 

 the comparison to shrubs and herbs, it more and more appears that the forms and types 

 which we count as peculiar to our Atlantic region, when we compare them, as we first 

 naturally do, with Europe and with our West, have their close counterparts 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 com- 

 mon that I should now not he greatly surprised if a Sarracenia or a Diona-a, 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 

 two of some peculiar kind gave one to us and the other to Japan, Manchuria, or the 

 Himalayas; when she had only one, divided these between the two partners on the 

 opposite side of the table. The result, as to the trees, is seen in these four diagrams. 

 As to number of species generally, it cannot he said that Europe and Pacific North 

 America are at all in arrears. But as to trees, either the contrasted regions have been 

 exceptionally favored, or these have been hardly dealt with. There is, as I have in- 

 timated, some reason to adopt the latter alternative. 



We may take it for granted that the indigenous plants of any country, particularly 

 the trees, have been selected by climate. Whatever other influences or circumstances 

 have been brought to bear upon them, or the trees have brought to bear on each other, 

 no tree could hold its place as a member of any forest or flora which is not adapted to 

 endure even the extremes of the climate of the region or station. But the character 

 of the climate will not explain the remarkable paucity of the trees which compose 

 tin- indigenous European forest. That is proved by experiment, sufficiently prolonged 



Ln Certain cases to justify the inference. Probably there is no tree of the northern 

 temperate /one which will not flourish in some part of Europe. Great Britain alone 

 eangroff double or treble the numbei of trees that the Atlantic states can. In all 

 the latter vreoan grow hanlh one tree of the Pacific coast. England supports all of 

 them, and ;ill our Atlantic trees also, and likewise the Japanese and North Siberian 

 species, which do thrive hen- remarkably in some part ^( the Atlantic coast, especially 

 the cooler temperate ones. The poverty of the European sylva is attributable to the 

 absence of om Atlantic American types, to its having do Magnolia, Liriodendron, 



A>imina. Negundo, DO iEsculus, none of that rich assemblage of leguminous trees 



represented by Locusts, Honey-Locusts, Gymnocladus, ami Cladrastis (even itsCerois, 

 which Is hardly European, Is like the Califbrnian one mainly a shrub) ; do Nyssa, oor 

 Liquidambar; DoEricacea ii>in^ to a tree; no Bumelia, Catalpa, Sassafras, Osage 

 Orange, Hiokory, or Walnut; and as to conifers, m> Hemlock Spruce, Arbor-vitas, 

 Taxodinm, DorTorreya. As compared with Northeastern Asia, Europe wants most of 



