154 ESSAYS. 
ones! But I would here mention certain cases as speci- 
mens. 
Our Lhus 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 (/?. 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 Linnzus, 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. 
