XX A NATURALIST IN WESTERN CHINA 



trable thickets, as dwarf Bamboos make travel on some of the 

 mountain slopes of Western China almost impossible. 



LiLiACE^. — Of this family Heterosmilax is found only in 

 eastern Asia, but Smilax occurs in the two regions, in each of which 

 it is about equally represented by a number of species ; Yucca and 

 Dasylirion are American. 



Arace^. — Plants of this family are sometimes woody in southern 

 China, where species of Pothos and Rhaphidophora are large 

 climbers, but in eastern North America all the members of this 

 family are herbaceous. 



PiPERACE^. — Piper, with woody species in southern China, is 

 the only genus of this family in the two regions. 



Chloranthace^. — Of this small tropical family Chloranthus, in 

 China, is the only representative in the two regions. 



Salicace^e. — In the number of species of Populus in the two 

 floras there is no great difference. None of the Asiatic species 

 grow to a larger size, perhaps, than the American Cottonwood 

 (Populus deltoidea Marsh.), but with this exception the Asiatic 

 species are larger and more valuable trees than the American 

 species, notably the Manchurian Populus Maximowiczii A. Henry, 

 and the north China Populus tomentosa Carr., which are among the 

 largest and most beautiful Poplar trees of the world. In Salix 

 there is probably no great difference in the number of species in the 

 two regions, although there is still much to be learned of the alpine 

 species of Western China. In eastern North America Willows are 

 mostly shrubby, only three or four species attaining to the dignity 

 of small trees, while in eastern Asia there are probably ten or twelve 

 arborescent species, and some of these are trees of considerable size. 

 JuGLANDACEiE. — In this family the advantage is with eastern 

 continental Asia, with four genera against two in eastern North 

 America, where there is no representative of Pterocarya, Engel- 

 hardtia, or Platycarya, Juglans is common to the two regions, but 

 Carya is not known in China ; and the presence in eastern North 

 America of this genus in many widely distributed species, valued 

 as timber trees and for the nuts produced by some of the species, 

 economically, at least, makes up for the absence of the three genera 

 which occur in China and not in eastern North America. Juglans, in 

 eastern America with three species, and continental Asia, with four 

 species, is of nearly equal importance in the two regions. None 

 of the Asiatic species, however, compare in size with the American 

 Juglans nigra L., but Juglans regia L., whose original home is now 

 believed to be on the mountains of northern and Western China, 



