Ray wrote:
(..a spur off of the discussion on abpo about orchids growing on tree
ferns.)

Question for the group:

Considering all of the growing media variants out there, how many of those
materials actually support orchids in the wild?

Coconut husk No
Douglas Fir bark No
Cork Oak bark No
Charcoal No
Perlite No

I think you should probably rule out the materials that don't occur
naturally. Otherwise, we might ask whether flowerpots support orchids
in the wild. Perlite is mined, but expanded perlite that we use is
manufactured from the mined material.

Sphagnum Maybe some very wet growing terrestrials, but I don't know of
any

IIRC, Habenaria repens, Pogonia ophioglossoides, Arethusa bulbosa.
Probably some others.