Gray • The Similarity Between the Flora of ]apan 



45 



these repetitions of east American 

 types in Japan and neighboring districts 

 are in all degrees of likeness. Sometimes 

 the one is indistinguishable from the 

 other; sometimes there is a difference of 

 aspect, but hardly of tangible character; 

 sometimes the two would be termed 

 marked varieties if they grew naturally 

 in the same forest or in the same re- 

 gion; sometimes they are what the 

 botanist calls representative species, the 

 one answering closely to the other, but 

 with some differences regarded as spe- 

 cific; sometimes the two are merely of 

 the same genus, or not quite that, but 

 of a single or very few species in each 

 country; in which case the point which 

 interests us is, that this peculiar limited 

 type should occur in two antipodal 

 places, and nowhere else. 



It would be tedious, and, except to 

 botanists, abstruse, to enumerate in- 

 stances; yet the whole strength of the 

 case depends upon the number of such 

 instances. I propose therefore, if the 

 Association does me the honor to print 

 this discourse, to append in a note a 

 hst of the more remarkable ones. But 

 I would here mention certain cases as 

 specimens. 



Our Rhus Toxicodendron, or poi- 

 son-iv}', is very exactly repeated in 

 Japan, but is found in no other part of 

 the world, although a species much like 

 it abounds in California. Our other 

 poisonous Rhus (R. venenata), com- 

 monlv called poison dogwood, is in no 

 way represented in western America, 

 but has so close an analogue in Japan 

 that the two were taken for the same 

 by Thunberg and Linnaeus, who called 

 them both R. vernix. 



Our northern fox-grape, Vitis La- 

 brusca, is wholly confined to the Atlan- 

 tic States, except that it reappears in 

 Japan and that region. 



The original Wistaria is a woody 

 leguminous climber with show blos- 

 soms, native to the middle Atlantic 

 State's; the species, which we so much 



prize in cultivation, W. sinensis, is 

 from China, as its name denotes, or 

 perhaps only from Japan, where it is 

 certainly indigenous. 



Our yellow-wood (Cladrastis) in- 

 habits a very limited district on the 

 western slope of the Allcghanies. Its 

 only and very near relative, Maackia, 

 is confined to Manchuria. 



The hydrangeas have some species 

 in our Alleghany region: all the rest 

 belong to the Chino-Japanese region 

 and its continuation westward. The 

 same may be said of Philadelphus, ex- 

 cept that there are one or two mostly 

 very similar species in California and 

 Oregon. 



Our May-flower (Epigaea) and our 

 creeping snow-berry, otherwise peculiar 

 to atlantic North America, recur in 

 Japan. 



Our blue cohosh [CaulophyUum] 

 is confined to the woods of the Atlantic 

 States, but has lately been discovered 

 in Japan. A peculiar relative of it, 

 Diphylleia, confined to the higher Allc- 

 ghanies, is also repeated in Japan, with 

 a slight difference, so that it may barely 

 be distinguished as another species. 

 Another relative is our twin-leaf {]ef- 

 fersonia) of the Alleghany region 

 alone: a second species has lately 

 turned up in Manchuria. A relative 

 of this is Podophyllum, our mandrake, 

 a common inhabitant of the atlantic 

 United States, but found nowhere else. 

 There is one other species of it, and 

 that is in the Himalayas. Here are four 

 most peculiar genera of one family, 

 each of a single species in the atlantic 

 United States, which are duplicated on 

 the other side of the world, either in 

 identical or almost identical species, 

 or in an analogous species, while noth- 

 ing else of the kind is known in any 

 other part of the world. 



I ought not to omit ginseng, the 

 root so prized by the Chinese, which 

 they obtained from their northern prov- 

 inces and Manchuria, and which is 



