139 



Hence the ratios of total number of the three groups are approxi- 

 mately as 360 : 220 : 250. The present author knows no reason why 

 this should be so ; probably there is no connection with the ratio 

 of the surfaces of the islands which is as 300: 119: 153. 

 Taking into consideration all the wild plants, except those which 

 are also found in the Old World and in North and South America, 

 the three Dutch Islands share 106 plants or 25/ more with. 

 South than North America and 42 plants or 10% more with 

 Central than North America. 



Comparing these numbers with the corresponding ones for the 

 flora of Portorico ! ), where they are 15 % and 7 %, we see that 

 the Dutch West Indian Islands contain relatively more Central 

 and South American plants than Portorico, although this island 

 has already a fairly large number of South American plants. 

 What Urban says (p. 681): ,,dass die Flora von Portorico die 

 starksten Beziehungen zu Sud-Amerika aufweist", holds still more 

 for Curagao, Aruba and Bonaire. 



Moreover we see that in the Dutch W. I. Islands 22 species or 

 11% occur which are besides only found in South America, 

 while for Portorico these numbers are 6 species or 0.3%. 

 This clearly proves that the flora of the three Dutch W. I. Islands 

 has a much greater resemblance with that of South America 

 than the Flora of Portorico has with the South American Flora. 

 All this refers only to the numerical distribution of the plants, 

 as given in the lists. 



With regard to the flora of Portorico we cannot make comparisons 

 as to the plants, determining the vegetation. Our discussion in 

 the Third Part Section C will show, however, that the flora of 

 Curasao, Aruba and Bonaire shows in many respects strong 

 tendencies towards that of the Antilles. 



i) I. Urban, 1. c., pp. 680, 681. 



