388 IN THE GUIANA FOREST. 



of water is below, and the plant seems to know 

 it. 



It is however in the aerial roots of orchids that 

 sensitiveness culminates. On living trees, round 

 logs, the bars of wooden baskets, and the sides of 

 porous flower-pots, they flow along as it were and 

 adhere so closely that it is impossible to remove 

 them without injury. The fact that their support 

 is congenial is so patent as to admit of no doubt 

 whatever. Let, however, the bark of the tree 

 become diseased, or the log begin to rot and the 

 change is at once noticeable. The fungoid growths 

 which develop under such circumstances are either 

 poisonous in themselves or indicate a condition of 

 things certainly deleterious to the orchid. The 

 aerial roots lose their vitality, unfasten themselves 

 from their perch, and sometimes prefer to fall 

 rather than remain exposed to contact with any- 

 thing so distasteful. In our garden we have seen a 

 plant loose itself entirely, and have had to pick it up 

 from the ground and fasten it to something more 

 congenial. Another example we have been watch- 

 ing for several months a plant of Burlingtonia 

 attached to a thin board by means of copper wire. 

 It has been established for about ten years, and 

 seems in very good health, flowering at regular 

 times, and adhering to its support until very lately 



