For an Orchid, rainforest can be a difficult environment, as light is the key factor, and the forest floor in a rainforest can be very dark indeed.
However, like the Hyacinth Orchid which I have discussed recently, this plant is also a "saprophyte". The Potato Orchid lacks the attractive flowers of the Hyacinth Orchid.
Another way to survive, as an Orchid in a rainforest, is to grow as an "epiphytic" plant, using trees as hosts, but not being parasitic upon them. In other words, just growing high in the branches of the trees, using them as a perch. This way, you can get all the light you need. Holding moisture is then the limiting problem.
The charming Orange Blossom Orchid (Sarcochilus falcatus) grows with its thick roots buried in the Rock Felt Fern (Pyrrosia rupestris) which grows thickly upon old Blackwood trees (Acacia melanoxylon). These mats of fern roots act like sponges holding plenty of moisture for the Orchid's roots.
Photo of the Orange Blossom Orchid at left. It gets its name from its sweet perfume.
The Dagger Orchid (Dockrillia pugioniformis) (formerly Dendrobium pugioniformis) is less showy, having tiny greenish flowers. It forms straggling masses of wiry roots which just hang from the branches of Sassafras and Coachwood trees. Apparently the roots are able to absorb enough moisture for the plants to survive.