UP IN THE TREES. 199 



got to the top of the tree, actually as well as 

 metaphorically, and we can hardly conceive of 

 further advance in that direction. Here and 

 there we find indications of the lines they have 

 followed, especially among the orchids, which, 

 taken altogether, are undoubtedly ahead of all 

 the rest. Thus the genus Catasetum contains 

 some species which live on the sand-reef, others 

 growing on low trees in the swamp, and one 

 which has found a congenial home among the leaf- 

 stalks of the eta palm. In the pure white sand 

 there is little more nourishment to be obtained 

 than on the trees in both places the plant can 

 obtain virtually nothing but air and moisture. 

 Going down to the pipe- clay savannah, is again 

 but a short step as the soil here is hardly more 

 fertile than the sand. Again, on the mountains, 

 orchids flourish indifferently on rocks or low trees, 

 and it can easily be understood that a tree growing 

 in a crevice may push out as it rises upward 

 the plant which has made itself fast to its young 

 stem or branches. 



However wonderful the habitat of the orchid 

 may be, it can not be compared with its other 

 developments. As we have seen, the leap into 

 the trees was but a short one, for which it had 

 long been prepared ; but what shall we say to the 



