re old orchid name

[GORDON RUTTER]

Hi there,
hopefully an answer for both your questions.
Your two species are synonymous, via Pognia trianthophora.
Index Kewensis (IK) is a publication (now on CD rom) listing the
first publicastion of names of species.  I initially looked up P.
pendula which showed no synonyms.  I then checked T. trianthophora
which said see P. trianthophora and upon looking at this it told me
this was synonymous with P. pendula.  The original publications for
all were given but unfortunately the dates were not.  Therefore I
can't say which has priority.
If you are interested in following this route IK on CD costs stlg1000,
perhaps your local herbarium has a copy you can consult or they may
have a set of the books it was first published as.  Afraid I don't
know of any way of getting this info from the net.
Hope this is useful

Gordon Rutter
Royal Botanic Gardens Edinburgh