INTRODUCTION xxxi 



Rhamnus, however, are more numerous in eastern continental Asia 

 than in eastern North America, and Rhamnus davuricus Pall., and 

 other Chinese species, from which a green dye is made, are more 

 valuable than any of the American species. 



ViTACE^. — Of the Grape family, three genera, Tetrastigma, 

 Ca5n"atia, and Leea, occur in China and not in eastern America ; and 

 Ampelopsis, Parthenocissus, and Vitis are common to the two 

 regions ; Cissus reaches tropical Florida but has not been reported 

 from southern China. Species of Vitis are less numerous in eastern 

 North America than in eastern continental Asia ; and in North 

 America there is no species which corresponds with the spiny- 

 stemmed Grape vines of China (Spinovitis). 



El^ocarpace^. — ^The forest flora of the two regions is only 

 represented by the Asiatic Elseocarpus and Sloanea (Echinocarpus) 

 of this family. 



TiLiACE^. — ^Tilia is widely distributed in the two regions with 

 rather more species in the Asiatic region. In size and in value as 

 ornamental trees there is not much difference between the American 

 and Asiatic Lindens. The Asiatic genera Grewia, Corchoropsis, and 

 Triumfetta do not appear in eastern North America. 



Malvace^. — In eastern North America there are woody species 

 in Pavonia, Hibiscus, and Thespesia, and in western continental 

 Asia only in Urena, Hibiscus, and Abutilon. 



BOMBACE^. — Only the Asiatic Bombax represents this family 

 in the woody plants of the two regions. 



Sterculiace^. — The large genus Sterculia has several Chinese 

 representatives, including Sterculia platanifolia L. f., now natural- 

 ized in several of the southern United States. Of this family these 

 genera also appear in China : Heritiera, Reevesia, Kleinhovia, 

 Helicteres, Pterospermum, Abroma, and Buettneria, among which 

 are several large trees, while in eastern North America are only 

 Hermannia, Melochis, and Nephropetalum, all small shrubs of arid 

 Texas. 



Dilleniace^. — Unrepresented in eastern North America, the 

 family appears in China in Tetracera, Actinidia, and Clemato- 

 clethra. 



THEACE.E. — Much more important in eastern continental Asia 

 than in eastern North America where only Gordonia and Stewartia 

 occur, this family has several woody plants in China, including Thea, 

 Gordonia, Stewartia, Schima,Ternstroemia, Eurya, Hartia,Tutcheria, 

 and Adinandra. One of the species of Thea, from the leaves of 

 which tea is made, is the most important member of the family ; 



