I posted this to OGD and the AOS forum a week ago or so but haven't
received the information I'm looking for, so now that I can post here
again, here it is:

I noticed this while gathering up the trichopilias as I tried to finish
the year's repotting before winter sets in (I repot outdoors in the back
yard because I have more room and I don't have to worry about the mess).
I have seen such things develop on the tops of pseudobulbs before on a
few oncidinae, but they usually don't mature and eventually die back.
These seem to be becoming viable plantlets, growing roots and even a
second growth on one of them.

I'd be interested in hearing from those in the know about these
adventitious growths - why they happen, how to encourage their
formation. I'm particularly happy to see these as they are on an
extremely rare and hard to obtain plant, T.eneidae.