TRAVELS IN BRAZIL. 531 



Thus we found on the shores of those immense 

 rivers, the Rio de S. Francisco, the Tocantin, the 

 Parnaiba, the Amazons and its collateral streams, 

 certain species which mark the particular charac- 

 ter of their vegetable forms, and are extremely in- 

 teresting to the enquirer into the geographical rela- 

 tions of the vegetable kingdom, because they in- 

 dicate, in a certain degree, the basis of the forms 

 of each individual Flora. Those shrubs and trees 

 which send out roots from their branches require 

 to come into contact with the sea, in order to at- 

 tain their perfect growth, and with their far-spread- 

 ing and very superficial roots appear especially to 

 affect the swampy soil of its shores. Though their 

 wood is very solid, and not untrequently thick, 

 they grow with extraordinary rapidity. The Rhi- 

 zophora mangle {mangue vermelho) is distinguished 

 by forming a very thick bark in a proportionably 

 short time. In those places where the scarcity of 

 wood does not make it necessary entirely to cut 

 down the mangle trees, as, for instance, in Maran- 

 hao, it is usual, particularly at the commencement 

 of the rainy season, when the sap begins to flow 

 between the wood and the bark, to tear off the lat- 

 ter, and use it for tanning. Wherever these trees 

 and shrubs grow, the whole neighbourhood is con- 

 verted into marshes and swamps, and serves only 

 as an abode for the abovementioned species of crab. 

 On the summits of these forests, growing on the 

 shore, we saw, as we sailed along, the most beautiful 



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