INTRODUCTION xxv 



and one in the south-eastern United States, and the latter with 

 one American and eight Chinese species. Micheha, Kadsura, and 

 the monotypic Manglietia and Tetracentron are Chinese, the 

 latter being one of the largest and most interesting of the Chinese 

 trees. 



Calycanthace^. — Calycanthus, with several species, is eastern 

 North American only, and Meratia (Chimonanthus), with two 

 species, is Chinese and does not appear in eastern North America. 



Anonace.e. — This tropical family reaches eastern North 

 America with several species of Asimina, its most northern repre- 

 sentative, and with Anona in tropical Florida. Uvaria, Artabotrys, 

 Unona, Polyalthia, and Melodorum represent it in south-eastern 

 tropical Asia. 



Laurace^. — In eastern North America this great, mostly 

 tropical, family appears only in Persea, Ocotea, Sassafras, Litsea, 

 Lindera, and Misanteca, but in eastern Asia there are eight genera 

 of Lauraceae, Cryptocarya, Beilschmiedia, Cinnamomum, Machilus, 

 Sassafras, Litsea, Lindera, and Cassytha. Of Sassafras there is 

 a species in each region, but the American species is a much more 

 widely and generally distributed tree, the Chinese Sassafras being 

 confined to the mountain slopes of western Hupeh and Szechuan. 

 Litsea, which appears in eastern North America in one small shrub, 

 in China is represented by at least a dozen species, among them 

 several small trees. Lindera, too, is more important in eastern 

 continental Asia than in eastern North America, where there are 

 only two shrubby species, while China can boast of nearly ten times 

 as many species ; some of these are large trees. The greater wealth 

 of China in plants of this family appears, too, in the important genus 

 Cinnamomum, including the species which yields the camphor of 

 commerce, and in Machilus, of which several species are large and 

 valuable timber trees. 



Capparidace^. — ^This family appears in the tropics of the two 

 regions with Capparis and Crataeva. Capparis is common to both, 

 but Crataeva of south-eastern China has no American representative. 



Nepenthace^. — One species of Nepenthes represents, in southern 

 China, this Old-World family of a single genus. 



Saxifragace^. — This family occurs in each of the two regions, 

 with Philadelphus, Hydrangea, Decumaria, Itea, and Ribes. Deutzia 

 (with one species in Mexico), Cardiandra, Schizophragma, Pileos- 

 tegia, and Dichroa occur in China but not in eastern North America, 

 which has no woody genus of the family not found also in eastern 

 continental Asia. 



