216 NATURAL AFFINITIES—INFERENCES. 
measure, to the physical features of the country, as well as 
to the circumstance that, off the coast the warm Japan 
current from the Indian Ocean, corresponding to the Gulf 
Stream, tempers the climate for a great distance inland. 
The flora of China and Japan is also observed to be anal- 
ogous to that of the United States.* 
The Zulu country of South Africa, the home of the im- 
phees, is of a more tropical character than that of Northern 
China, but is greatly modified by the variable nature of the 
surface, which is low and flat along the coast, abounding 
in forests and jungles, but becoming undulatory and more 
elevated toward the base of the mountains which form the 
edge of the great central plateau beyond, much as in the 
north of China. The flat land enjoys an almost tropical 
temperature — figs, oranges, pomegranates, almonds and 
cotton flourishing luxuriantly. Along the hillsides, toward 
the interior, maize, melons, pumpkins, and a species of 
millet, called Caffre corn, grow to a fine size. The great 
diversity of climate, afforded by differences of elevation, 
renders it difficult, in the absence of definite information, to 
determine the natural habitat of the imphee. 
Almost every variety of soil and surface is there pre- 
sented, from the low-lying coast-land and the rolling 
country beyond, varying gradually as the traveler ascends 
the declivities of mountains clad in the foliage of temperate 
climes, to the snow-line. 
The mean annual temperature of this portion of Caffraria 
is the same as that of the northern half of China. 
One of the most important facts which have been disclosed 
by the cultivation of sorghum cane in our own country, is its 
great capacity for variation; some of the varieties have 
markedly changed in some of their most important quali- 
—— 
* Agassiz and Gould, Comp. Zool., p. 203. 
