“The plant is so rare because it is basically impossible to propagate. It has no leaves, does not depend on photosynthesis and does not manufacture its own food. Like the Lady slipper, it needs a specific fungus in close contact with its root system, which feeds it. The Ghost orchid never grows leaves, and will therefore always depend on the fungus for its nourishment. The Ghost orchid can live underground for years, without showing any external signs and will only bloom when all conditions are optimum. This explains why some orchid enthusiasts search for years and years just to have a glimpse of this elusive flower.” Via.
I always read about it in books and it is really hard to see one.