I spent the morning working on Octomerias and decided to have a look at your plant again. It is a yellow flowered variant of Octomeria palmyrabellae Barb. Rodr. This species was described as having white flowers with purple stripes and this is the form I remember have seen in bloom Rio de Janeiro Botanical Gardens many years ago. However, I had a  look at the internet and found a few a pictures of this species. The color of the flowers actually varies from white, yellow or greenish background with purple stripes to full yellow flowers.
To tell you the truth I am not sure whether or not this is O. juncifolia. I can't see the characteristic "inflated" Â sheaths on the ramicauls and the lip 1/2 apical portion of the lip looks much longer than in the 'typical" juncifolia. In order to be sure a specimen for study would be mostly welcome.