INTRODUCTION xxxv 



Oleace.e. — In this family also the advantage is with eastern 

 continental Asia, with eight genera, while only four are eastern 

 North American. Fraxinus, Chionanthus, and Osmanthus are 

 common to the two regions, Adelia is American only, and Fontanesia, 

 Forsythia, Syi^inga, Ligustrum, and Jasminum are Chinese and not 

 American. Fraxinus is widely distributed in each of the two 

 regions, with probably about the same number of species in each, 

 but the American species are usually larger and more valuable 

 timber trees. As an ornamental plant the American Chionanthus 

 is superior to the Chinese representative of the genus, but China's 

 contributions to gardens from this family in Forsjrthia, Syringa, 

 Ligustrum, and Jasminum more than make up for the beauty of the 

 American Chionanthus. 



LoGANACE^. — Gelsemium, with one species, and Buddleia, with 

 a species of southern Texas, are the only woody representatives of 

 this family in eastern North America. These genera occur in 

 China with Strychnos, Gasrtnera, and Gardneria. 



Apocynace^. — Vallesia, Thevetia, and Trachelospermum are 

 woody plants of this family in eastern North America. It has a 

 larger representation in southern China in Plumeria, Melodinus, 

 Rauwolfia, Alyxia, Alstonia, Parsonsia, Pottsia, Wrightia, Ecdy- 

 santhera, Anodendron, Trachelospermum, and Scindechites. 



AscLEPiADACEiE. — Roulinia, with a species of southern Texas, 

 is the only woody plant of this family in eastern North America, 

 but in eastern continental Asia occur woody species of Pentaneura, 

 Cryptolepis, Periploca, Taxocarpus, Calotropis, Holostemma, 

 Graphistemma, Metaplexis, Henrya, Gymnema, Marsdenia, 

 Stephanotis, Pergularia, Dregea, and Hoya. 



CoNVOLVULACE^. — Ipomoea and Argyreia are Chinese representa- 

 tives of this family, and a woody species of Ipomoea has reached 

 Florida from the tropics. 



BoRRAGiNACE^. — Cordia, Bourreria, and Ehretia are the North 

 American genera of this family, with woody species. Cordia and 

 Ehretia appear in China in a larger number of species than in 

 eastern North America, and Tournefortia is Asiatic and not 

 American. 



Verbenace^. — Aloysia, Lantana, Citharexylon, Duranta, Calli- 

 carpa, and Avicennia, represent this family in the southern United 

 States. In China, Callicarpa, with several species, Premna, Gmelina, 

 Vitex, Clerodendron, Caryopteris, Sphenodesma, and Avicennia 

 make a larger representation of the family, only Callicarpa, with one 

 American species, and Avicennia occurring in the two regions. 



