While orchid seedlings often require a Basidiomycete fungal symbiont, it is probably not necessary for the, in this case Amanitaceae, to be epiphytic. Most are mycorrhizal with trees; thus their spores can easily travel into canopies. The orchid-fungus relationship might result in an incomplete life cycle for the fungus.

Another question is: Could your data be pointing to the Tricholomataceae ? This is a very diverse and widespread family. Some, such as Micromphale, are known to grow on dead branches and twigs.

It would be interesting to plate out the fungus and discover what you've found.

Trying to get detailed information