264 IN THE GUIANA FO&EST. 



is drawn towards the other, and, perhaps slip- 

 ping off, hangs downward as if held by a 

 number of strings. In such a position it has 

 great difficulty in recovering itself, but in time 

 again raises its head and is apparently as flourish- 

 ing as before. Although the aerial roots are mainly 

 concerned with securing the orchid on its perch, 

 they also appear to help the leaves, by absorbing 

 moisture, and even in some cases to assimilate 

 the vegetable infusions which continually trickle 

 down the tree-trunk and branches. This liquid 

 manure, however, does not seem to be absolutely 

 necessary, although it may probably be of ad- 

 vantage when obtainable. 



We have seen how different species accommodate 

 themselves to their positions and produce nodding 

 or drooping flower-spikes to suit. This is just 

 as strikingly exemplified in different individuals. 

 When the flower-spike is free from obstruction 

 it grows outward or downward as the case may 

 be, without altering its course, but when it is 

 crowded by other plants or its own pseudo-bulbs 

 the case is different. Then, the young spike 

 grows upright as far as is necessary, and then 

 gracefully arches over until the flowers can hang 

 free. It follows therefore that the peduncle is 

 longer or shorter according to circumstances. 



