62 THE WORLD OF LIFE 



the cataracts of the Orinoco to the mountaius of Matto Grosso. 

 Taking the fact that by moving away a degree of latitude or 

 longitude I found about half the plants different as a basis, 

 and considering what very narrow strips have up to this day 

 been actually explored, and that often very inadequately, by 

 Humboldt, Martins, myself, and others, there should still 

 remain some 50,000 or even 80,000 species undiscovered. To 

 any one but me and yourself, this estimation will appear most 

 extravagant, for even Martins (if I recollect rightly) emits 

 an opinion that the forests of the Amazon contain but few 

 species. But allowing even a greater repetition of species than 

 I have ever encountered, there cannot remain less than at least 

 half the above number of species undiscovered." ^ 



Spruce was one of the most careful and thoughtful of writers, 

 and would never have made such a statement without full con- 

 sideration and after weighing all the probabilities. In the 

 same letter he describes how, when leaving the Uaupes River 

 after nine months of assiduous collecting there in a very lim- 

 ited area, a sunny day after continuous rains brought out' 

 numerous flowers, so that as he floated down the stream he 

 saw numbers of species quite new to him, till the sight became 

 so painful that he closed his eyes to avoid seeing the floral 

 treasures he was obliged to leave ungathered ! At Tarapoto 

 he observed that some flowers opened after sunset and dropped 

 off at daAvn, so that they would be overlooked by most collectors, 

 while of many the flowering season was very limited, sometimes 

 to a single day. Join to this the scarcity of individuals of 

 many species scattered through a trackless forest, and it is evi- 

 dent that the true floral riches of these countries will not be 

 fully appreciated till numerous resident botanists are spread 

 over the entire area. 



From the facts of distribution given by Mr. Hemsley we 

 learn that about one-twelfth of the species of Central America 



1 See Spruce's Xotes of a Botanist on the Amazon and Andes, vol. ii. p. 

 208. 



