AMAZONIAN VEGETATION 35; 



to have taken up their exclusive abode : such are 

 Commianthus among Rubiaceae, Pagamea among 

 Loganiacese, Myrrnidone and Majeta among Melas- 

 tomaceae ; and there are a few other peculiar genera, 

 chiefly monotypic. But, of the riparial plants, 

 nearly every species has its congener on terra 

 firme, to which it stands so near that, although 

 the two must of right bear different names, the 

 differences of structure are precisely such as might 

 have been brought about by long exposure even 

 to the existing state of things, without supposing 

 them to date from widely different conditions in 

 the remote past ; and this is especially true of such 

 genera as Inga, Pithecolobium, Lecythis, and of 

 many Myrtles and Melastomes, Sapotads, etc. 



As an illustration of the features which tend to 

 impress a certain character of uniformity on the 

 vegetation of the Amazon region, I will take the 

 case of a single tree, Bertholletia excelsa (H. and B.) 

 -perhaps the noblest tree of the Amazon region, 

 and the most characteristic of its Vircrin Forests 



o 



and briefly sketch its distribution. In aspect and 

 foliage it is not unlike a gigantic Chestnut tree ; 

 and the seeds (the Para nut of commerce), if not 

 much like chestnuts in their trigonous bony shell, 

 are not very different in taste, whence the Brazilian 

 name of the tree, " Castanheira," and of the seeds 

 " castanhas." This tree is found almost throughout 

 the Amazon valley, both to north and south, chiefly 

 wherever there is a great depth of that red loam 

 which it pleases M. Agassiz to call "glacial drift." 

 About Para itself there is no lack of it, especially 

 in the fine woods of Tauaii ; and 1200 miles farther 

 to the west it may be seen in some abundance- on 



