EXCUKSION ON THE RIO NEGRO. 339 



or peccan-nut trees, so readily distinguished on the lower 

 course of the Mississippi, or the different kinds of oaks, 

 birches, beeches, or walnut-trees which attract observation 

 when sailing along the shores of our Northern lakes. It 

 seems, however, impossible to discriminate between all the 

 trees of .this wonderful Amazonian forest ; partly because 

 they grow in such heterogeneous associations. In the 

 temperate zone we have oak-forests, pine-forests, birch, 

 beech, and maple woods, the same kinds of trees con- 

 gregating together on one soil. Not so here ; there is 

 the most extraordinary diversity in the combination of 

 plants, and it is a very rare thing to see the soil occu- 

 pied for any extent by the same kind of tree. A large 

 number of the trees forming these forests are still unknown 

 to science, and yet the Indians, those practical botanists 

 and zoologists, are well acquaiyted, not only with their 

 external appearance, but also with their various properties. 

 So intimate is their practical knowledge of the natural ob- 

 jects about them, that I believe it would greatly contribute 

 to the progress of science if a systematic record were made 

 of all the information thus scattered through the land ; an 

 encyclopaedia of the woods, as it were, taken down from 

 the tribes which inhabit them. I think it would be no bad 

 way of collecting, to go from settlement to settlement, send- 

 ing the Indians out to gather all the plants they know, to 

 dry and label them with the names applied to them in the 

 locality, and writing out, under the heads of these names, 

 all that may thus be ascertained of their medicinal and 

 otherwise useful properties, as well as their botanical char- 

 acter. A critical examination of these collections would at 

 once correct the information thus obtained, especially if the 

 person intrusted with the care of gathering these materials 



