162 



OEIGINAL ARTICLES. 



types, possessing 26 Nat. Orders uot in Europe, while Europe lias 

 only 7 to 10 orders absent from the States. Nevertheless the Euro- 

 pean families give character to the vegetation. Dr. G-ray says 

 farther, that of these 26 orders 20 have their principal development 

 in troi^ical regions, while 3 of the remaining orders have tropical or 

 sub-tropical representatives.* This circumstance is noteworthy when 

 we consider that the mean annual temperature of the Northern 

 States is lower than that of "Western Europe. 



I find about 300 genera (Dicots. 21'2, Monocots. 00) are common 

 to the Southern States and Japan. To this number the Northern 

 States add 33 (Dicots. 24, Monocots. 9), making a total of 330—340 

 in Eastern North America. The Japanese orders not represented 

 in the Eastern States are as follow, with the number of their genera 

 and species. 



About 320 Japanese genera (Dicots. 274, Monocots. 50) are absent 

 from the States ; of these the most remarkable and characteristic of 

 the Japan Flora seem to belong to Berberideae and Lardizabaleae, 

 Ternstrcemiaceae, Zanthoxylaceae and allies, Eosaceae, Laiu'aceae, 

 and Coniferae. 



A marked difference has been indicated (supra) between the 

 Floras of the East and West Coasts of North America in the relatively 

 small number of species common to these Floras as compared with 

 the number common to the Eastern States and Europe. Dr. G-ray, 

 in his memoir on the Japanese Flora,t points out that there are 

 fewer Japanese species represented in West North America than in 

 Europe, while there are more in East North America than in either. 

 If strictly identical species alone be regarded, however, the European 

 proportion is favoiu-ed. In his table, including 580 Japanese entries, 



* The same botanist points out tlie almost complete deficiency of forms peculiar 

 to West Europe in Temperate America ; a deficiency remarkably contrasting with 

 the large niunber of East American forms repeated or represented in Eastern Asia. 

 The only genera divided between East North America and Europe which Dr. A. 

 Gray can find are Ostrya, Narthecium, Psamma, Cakilc, Scolopciulr'mm ? 



t 1. c. p. 437. 



