xviii A NATURALIST IN WESTERN CHINA 



larger mountain systems, the greater height of land, and its more pro- 

 lific neighbours can account for a larger number of genera in eastern 

 Asia than in eastern North America, it is not possible to find an 

 explanation for the greater number of species there of widely 

 distributed genera like Acer, Picea, Prunus, Sorbus, and Berberis, 

 which are more numerous in China than in any other part of the 

 world, or for the absence from eastern Asia of larger numbers of 

 species in genera like Crataegus and Amelanchier. 



In eastern continental Asia there is nothing to compare with 

 the great maritime pine belt which extends from southern Virginia 

 to eastern Texas, and is one of the remarkable features of the flora 

 of eastern North America ; and the great forests of Pinus Strobus L., 

 which once extended from northern New England and eastern 

 Canada to northern Minnesota, are but poorly replaced in north- 

 eastern Asia by trees of Pinus koraiensis S. and Z., scattered over a 

 comparatively restricted area in eastern Siberia and Korea. The 

 Black Oaks, with their lustrous leaves and biennial fructification, 

 which are so abundant and conspicuous, except in the extreme north, 

 all over eastern North America, are wanting in eastern x\sia ; while 

 the Bamboos, the most widely distributed and the most generally 

 useful of all the forest plants of China, are represented in North 

 America by two small and unimportant species of Arundinaria 

 confined to the swamps and river bottoms of the southern states. 



As a rule, to which, of course, there are a few exceptions, the 

 trees of eastern North America are larger and more valuable than 

 related Chinese species ; but of Chinese shrubs it can be said gener- 

 ally that they produce more beautiful flowers than the shrubs of 

 eastern North America, although to this statement there are also 

 some exceptions. A more detailed examination of the principal 

 groups of forest plants in the two regions will show the similarities 

 and the differences of the forest flora of the two regions. 



Cyc ADAGES. — Four species of Cycas are found in southern 

 China, and in Florida the family appears in two species of Zamia. 



Conifers. — This family is represented in China by fourteen, 

 and in eastern North America by nine, genera. In eastern North 

 America there are only two genera which are not also represented 

 in China, Taxodium, which is replaced there by the nearly related 

 Glyptostrobus and Chamaecyparis, represented, however, in Japan 

 by two important trees. Libocedrus, Cupressus, Cunninghamia, 

 Pseudolarix, Keteleeria, and Fokienia have no eastern American 

 representative. In Pinus, eastern North America, with fifteen 

 species, has the advantage of eastern continental Asia, in which 



