Leafless orchids

[Stray59]

I thought that with the myco-heterotrophic forms, you also have to provide the fungus that provides them with a sugar / food source? If so, where do you get the fungus?
If not, how do they get food with no chlorophyll?
Steve
P.s. - on the "Learn something new everyday" level - I did not realize there was a myco-heterotrophic cymbidium! How wild - will look that one up - !
Thnaks