46 PHYTOGEOGRAPHY AND EXPLORATION 



now known to inhabit Korea and the two to settle. So far as we know, 

 northern Japan. The Jesuit Fatliers they are just ahke; and, even if some 

 identified the plant in Canada and the difference were discerned between 

 Atlantic States, brought over the Chi- them it would not appreciably alter the 

 nese name by which we know it, and question as to how such a result came 

 established the trade in it, which was to pass. Each and every one of the 

 for many years most profitable. 'Hie analogous cases I have been detailing- 

 exportation of ginseng to China prob- and ver\' many more could be men- 

 ably has not yet entirely ceased, tioned— raises the same question, and 

 Whether the Asiatic and the atlantic would be satisfied with the same an- 

 American ginsengs are to be regarded swer. 



as of the same species or not is some- Tliesc singular relations attracted 



what uncertain, but they are hardly, if my curiosity early in the course of my 



at all, distinguishable. botanical studies, when comparatively 



There is a shrub, Elliottia, which is few of them were known, and my seri- 



so rare and local that it is known only ous attention in later years, when I 



at two stations on the Savannah River had numerous and new Japanese plants 



in Georgia. It is of peculiar structure, to study in the collections made, by 



and was without near relative until Messrs. Williams and Morrow, during 



one was lately discovered in Japan Commodore Perry's visit in 1853, and 



(Tripetaleia) , so like it as hardly to be especially, by Mr. Charles Wright, of 



distinguishable except by having parts Commodore Rodgers's expedition in 



of the blossom in threes instead of 1855. I then discussed this subject 



fours— a difference not uncommon in somewhat fully, and tabulated the facts 



the same genus, or even in the same within my reach, 



species. This was before Heer had developed 



Suppose Elliottia had happened to the rich fossil botany of the arctic zone, 

 be collected only once, a good while before the immense antiquity of exist- 

 ago, and all knowledge of the limited ing species of plants was recognized, 

 and obscure locality were lost; and and before the publication of Danvin's 

 meanwhile the Japanese form came to now famous volume on the "Origin of 

 be known. Such a case would be paral- Species" had introduced and familiar- 

 lel with an actual one. A specimen of ized the scientific world with those now 

 a peculiar plant {Shortia galacifolia) current ideas respecting the histor\' and 

 was detected in the herbarium of the vicissitudes of species with which I at- 

 elder Michaux, who collected it (as his tempted to deal in a moderate and 

 autograph ticket shows ) somewhere in feeble way. 



the high Alleghany Mountains, more My speculation was based upon the 



than eighty years ago. No one has seen former glaciation of the northern tem- 



the living plant since or knows where perate zone, and the inference of a 



to find it, if haply it still flourishes in warmer period preceding and perhaps 



some secluded spot. At length it is following. I considered that our own 



found in Japan; and I had the satisfac- present vegetation, or its proximate an- 



tion of making the identification. A cestry, must have occupied the arctic 



relative is also known in Japan; and a and subarctic regions in Pliocene times, 



less near one has just been detected in and that it had been graduallv pushed 



Tibet. southward as the temperature lowered 



Whether the Japanese and the Alle- and the glaciation advanced, even be- 



ghanian plants are exactlv the same or yond its present habitation; that plants 



not, it needs complete specimens of of the same stock and kindred, prob- 



