154 ESS A YS. 



ones. 1 But I would here mention certain cases as speci- 

 mens. 



Our Rhus Toxicodendron, or Poison Ivy, 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 ( i?. venenata), commonly 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 Labrusca, is wholly con- 

 fined to the Atlantic States, except that it reappears in Japan 

 and that region. 



The original Wistaria is a woody leguminous climber with 

 showy blossoms, native to the middle Atlantic States ; the 

 other 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) inhabits a very limited dis- 

 trict on the western slope of the Alleghanies. Its only and 

 very near relative, Maackia, is in Mandchuria. 



The Hydrangeas have some species in our Alleghany re- 

 gion ; all the rest belong to the Chino-Japanese region and 

 its continuation westward. The same may be said of Phila- 

 delphus, except that there are one or two mostly very similar 

 species in California and Oregon. 



Our Blue Cohosh (Caulophyllum) is confined to the woods 

 of the Atlantic States, but has lately been discovered in 

 Japan. 2 A peculiar relative of it, Diphylleia, confined to the 

 higher Alleghanies, 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 (Jeffersonia) of 

 the Alleghany region alone ; a second species has lately turned 

 up in Mandchuria. 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 

 1 See Appendix, I. 2 Appendix, II. 



