This pretty Sun Orchid is a late flowerer, by comparison with all the others which I find here in the Southern Highlands of NSW. Most of them have their peak around the first weekend of November. These plants are flowering for the first time this year, on 11 December. I previously saw this plant flowering, in the same place, on 4 December 2007. Allowing a few days for delay because of the rain we have had this year, this flowering event is about on that same schedule - roughly the end of the first week in December - and importantly, a full month later than most other Sun Orchids in this district.
I have checked for these plants several times in recent weeks. Eventually, on Wednesday this last week, I found two plants which were in bud, which I was able to confirm as being on this species.
But I needed them to open fully to properly record the species, its true nature, and get it established on the public record for the Southern Highlands.This plant is Thelymitra circumsepta. It is reported as flowering in December/January, and growing in soaks, in high rainfall areas. Bingo!
The pink or reddish colour of the top of the "column" (the "Post-anther Lobe") and the yellow tufts on the "lateral arms" of the column are diagnostic of this species. Colin Rowan reports very similar flowers (from Victoria), but lacking the reddish colour on the column. Everything else looks the same. His plants from Tasmania have the pink "post-anther lobe".
I cannot quite make out the details of the bead of moisture held in the lateral arms of this flower. I did not notice this detail until I got back home, at the end of along day.
As these plants are growing adjacent to a road, in an area which the SCA has slashed, traditionally. I have asked the local supervisor to not allow slashing in this and other areas until winter, when any slashing tractors will do minimal damage to the flowering Orchids. At the moment is it simply too wet to allow tractors into this area.