Orchids of the Captains Flat Cemetery: confusion vegefied!

As I cannot make it to the ANPS WW next week, and we were going to the Flat to visit Ingrid, Frances suggested we go to the Cemetery to try to find the famous orchids a couple of days early.  It was fantastic, but we came away with more doubts than certainties.

I initially posted some photos which allowed our more our more expert friends to make some suggestions about ID things and and have then done some revisions.

Let us begin with Diuris.  The first image has been confirmed as D. semilunulata while the second doesn't seem to match anything.  I would take a shot at something close to Golden Moths (D chryseopsis), but:

1. the presence of some brown tends to kibosh that! and
2. D chryseopsis fnished flowering at home several weeks ago (more than would be expected  from the 200m altitude difference).

The upshot seems to be that D behrii (Large Golden Moths) have been recorded in the cemetery and they are promiscuous little beasts so could have hybridised with the D semilunulata!

I think I have a fair handle on Stegastyla and these fitted S moschata better than any of the others (fair bit of purple, teeth not going round the bend). I ruled out S cucculata as the purple was not extensive enough .

Now we get to the exciting and VERY frustrating bit.  Sun Orchids.  There was a wall of these!!  It was magnificent.  But could we identify them with certainty? We could not in several cases.  However here are my snaps and comments which may allow others to make suggestions.  Frances does have better images of some of the plants but it rapidly got into the situation of "too much information".  If we are able to ID these we will subsequently pick the best images and update this page.

Cutting to the chase there seems to be some general agreement that in the past Thelymitra ixioides would have been the main suspect of all the following.  See, in particular, the very helpful comment from Denis Wilson.  This is not shown in the Field Guide to the Orchids of the ACT as the species is now not thought to occur in that administration (presumably it left in protest at self-Government).   The next bunch of  images are included to show the level of variation which confuses a poor soul such as myself.  Another observer, revisited the site a few days later and (unusually for this genus) the plants were flowering.  He concluded all were T ixioides - possibly some of these were not the plants flowering a few days earlier. 

Let us start with a sun orchid with no spots and green leaf base.

We now move on to the measles ward.  That is, sun orchids with spots. There are several of these and we had much trouble trying to fit images to descriptions.  As above we have a full flower image followed by a cropped image.

And then again possibly not!

One could ask what about Prasophyllum petilum: the endangered Tarengo Leek orchid which is what we were actually hoping to see.  One might indeed ask but I have got no answers.  It was absent as far as we could tell - apparently they are late bloomers so may not have stuck their heads up above the parapet thus far.