Anoectochilus really brings us on the right genus track, Jean!
I searched on the 'Flora do Brasil' It said none of the genus occurs in Rio de Janeiro state but when I searched for the whole of Brazil it came with two species:
http://floradobrasil.jbrj.gov....
Anoectochilus argenteus and Anoectochilus pictus.
I feel sure it is Anoectochilus argenteus!
I think plants often don't know they shouldn't occur in another state than mentioned in the Flora do Brasil..
https://www.google.be/search?q...