xxviii A NATURALIST IN WESTERN CHINA 



Cercis, Cassia, Gleditsia, Gymnocladus, Sophora, Cladrastis, Wisteria, 

 Erythrina, Desmodium, Lespedeza, Dalbergia, and Sesbania. 



RuTACEiE. — In eastern Asia representatives of this family are 

 certainly more important than those found in eastern North 

 America, for they include Citrus, Limonia, Atalantia, two genera 

 of interesting trees, Phellodendron and Evodia, besides Toddalia, 

 Acronychia, Murraya, Clausena, Orixa, and Skimmia, while in eastern 

 North America this family is represented only by Helietta, Ptelea, 

 Amyris, and by Zanthoxylum which occurs also in the other region 

 which contains the larger number of species. 



Zygophyllace^ is represented in eastern North America by 

 Guaicum and Porlieria, and in eastern continental Asia by 

 Zygophyllum. 



CocHLOSPERMACEiE. — A species of Amoreuxia in southern Texas 

 is the only member of this family in the two regions. 



SiMARUBACE^ appear in tropical Florida in a species of Sima- 

 ruba and in Picrasma, and in Texas in Castela, while of this family 

 China has given to the world one of its valuable trees in Ailanthus, 

 and is also represented by Picrasma, Brucea, and Harrisonia. 



BuRSERACE^. — One species of Bursera is eastern North American, 

 and the species of Canarium in China represent this family in the 

 two regions. 



Meliace^. — Of the woody plants of this family in the two 

 regions Swietenia is certainly the most valuable, although it is the 

 only eastern American representative of the family ; while in China, 

 representatives of this family are Aglaia, Amoora, Turraea, Cedrela, 

 and Melia, one species of the last being widely and generally 

 naturalized in the southern United States. 



Malpighiace^. — ^This family reaches tropical Florida with a 

 species of Byrsonima and southern Texas with a species of Mal- 

 pighia : its only genus in China is Hiptage. 



PoLYGALACEiE. — Of this family only a few Chinese species of 

 Polygala are frutescent, the species of this genus in eastern North 

 America being herbaceous. 



DiCHAPETALACE^. — This small family is represented in the two 

 regions by a single species of Dichapetalum in south-eastern China. 



EuPHORBiACE^. — Woody plants of this family are more 

 numerous in China than in eastern North America, where the follow- 

 ing genera only appear : Andrachne, Drypetes, Croton, Ditaxis, 

 Ricinella, Bernardia, Gymnanthes, Sebastiana, Stillingia, Hippo- 

 mane, and Mozinna. These eastern North American representatives 

 of the family are all small shrubs with the exception of Drypetes, 



