In the last few days, I have found a batch of tall Sun Orchids, growing down in the Kangaloon area. These plants are very strong growers. Some of which have been pollinated already (but the books refer to self-pollination occurring). But others are still in bud. However, like many Sun Orchids, they are shy to flower. The weather of the last few days has been sunny, and warm, but not really quite enough to persuade these flowers to open properly.
I managed to find one flower opening up (just). But, it was enough to see the distinctive column, and the so-called "post anther lobe", and the column arms.
This flower has a very short "post-anther lobe" (the structure behind the column), which is distinctively pinkish. The yellow column is clearly visible in the photo below. The "column arms" are very densely brush-like, and a clear yellow.
The plants are very tall - the tallest Sun Orchids I have seen, probably up to 800mm high. And they are growing in a wet peaty swamp (there is free water lying in patches). And the flowering time is later than any other Sun Orchids in the area.
This annotated photo shows the height of the plant, the large green leaf curving off to the right, from the base of the stem, and two so-called "sterile bracts" on the stem. All these details match the description of Thelymitra circumsepta, the so-called Naked Sun Orchid. I will keep monitoring these plants over the next week, and see if I get a nice hot, sunny day, which might prompt some more flowers to open.