490 PHYLOCEOGRAPHICAL REMARKS. 



long Stay in the colony and seldom collected a species already found. 



In regard to French Guyana I believe that the second factor has the 

 greatest influence, namely that the flora is less known. For this country 

 has certainly been much less visited by collectors than Surinam. This 

 appears best of all from the figure for the Orchidaceae Of the 142 orchids 

 known in Surinam, 42 also occur in French Guyana and 75 in British 

 Guyana Now, since the orchids are the family to which collectors as a rule 

 pay most attention, we may safely infer that the flora of French Guyana 

 is much less known than that of Surinam, since it cannot be assumed that 

 French Guyana should be so much poorer in orchids than the adjoining districts. 



When making a comparison with the Amazon region both factors make 

 themselves perhaps equally felt in the differences between the numbers of 

 species. Especially the much greater extent of this region must lead neces- 

 sarily to a greater wealth of species, but also the collections have heen 

 made on a much larger scale and the travellers have as a rule stayed 

 much longer. 



Looking at the total figures one sees that of the 2 10 1 species known 

 in Surinam 1273 or 60.6% are also known for French Guyana, 1250 or 

 59i5 % also for British Guyana and 1287 or 61.3 % also for the Amazon 

 district. Hence if it is true that the flora of British Guyana is much better 

 known than that of Surinam, that of French Guyana less well known, it 

 follows that the systematic constitution of the flora of Surinam has more 

 resemblance with that of French than with that of British Guyana. But one 

 thing must not be lost sight of, namely that there has been more collected 

 in the east of Surinam than in the west and although it has not been 

 proved at all that the flora of the east differs from that of the west, yet 

 it is striking that from the Marowine, the Gonini and the Tapanahoni so 

 many plants have become known which until now had only been found in 

 French Guyana. 



The number of endemic species is no less than 293 or 14%, a percen- 

 tage which will probably be increased by a monographic treatment of the 

 different families. In this respect Surinam consequently agrees entirely with 

 Guyana and the Amazon district, where also the number of endemic species 

 is so uncommonly large. Remarkable is the very limited distribution which 

 such endemic plants have. From the systematic part it will be seen that 

 many of these species have been found twice or more, but nearly always 

 in very neighbouring places, e. g. along the same river. 



These species nearly always belong to the vegetation of the primitive 

 wood which is in complete agreement with the fact that wood plants 

 generally have far fewer means of spreading their seeds than the plants 

 of the savannah and other small growths occurring in open places, 

 along roads, etc. In this respect the flora of the Surinamian savannahs 

 presents nothing peculiar. Nearly all the plants, especially the herbs, are 

 inhabitants of the whole of tropical America, as well as the great majority 



