UP IN THE TRE2S. 261 



now entirely suited to its habitat, and flourishes 

 to perfection in places where few other orchids 

 succeed in establishing themselves. Instead of 

 a hollow pseudo-bulb, the Coryanthes provides 

 an oval mass of fibrous roots, as distinct from 

 those so well known in the other orchids as their 

 object is different In the Coryanthes the ants 

 establish themselves, filling up the interstices to 

 make a waterproof nest, whence they are ready to 

 issue on the least alarm of an enemy. Being 

 carnivorous they can do the plant no harm, but, 

 on the contrary, are so useful that without them 

 it suffers greatly from cockroaches and other pests. 

 This is easily proved by specimens brought to 

 our gardens, where, on account of the collectors 

 having removed their useful tenants by soaking 

 them in water, they are particularly subject to the 

 attacks of insects and rarely thrive for any length 

 of time. The nearly-allied Gongoras also make 

 a less perfect provision for ants, and the great 

 Ondidium altissimum often has such large com- 

 munities that the collector finds it very difficult 

 to dislodge the plant from its perch without 

 getting severely bitten. Here we see a gradual 

 transition from long aerial roots running in every 

 direction, and a massing together of an intricate 

 maze of fibres. 



