Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Monday, November 12, 2007

The Day of the Sun Orchids

Today was a lovely sunny day (after what seemed like weeks of rain). So, naturally I went out in the local bushland, to check out my favourite haunts of Sun Orchids.

These plants are named Sun Orchids for a very good reason - they generally open only on really sunny days. The east coast members of this genus generally have bright blue flowers, resembling the clear blue skies under which they open their flowers (there are some exceptions, of course).
Thelymitra kangaloonica has distinctively veined flowers.

I have been monitoring some plants of a newly-named species Thelymitra kangaloonica. It is named for obvious reasons, from its location in Kangaloon.
The yellow cap of the "column" of Th. kangaloonica
is distinctively shaped and fringed.
This following plant is as yet unidentified (by me). It is possibly the "Tall Sun Orchid" Thelymitra media***. This is a tall plant, with 7 flowers on the stem. It is growing in tall Eucalypt forest. Its colour is almost "electric blue" - a brilliant colour, with great intensity. It is not a true dark blue, but as it grows in a forested area, which makes the flower appear darker than it actually is. This plant does not have any of the pinkish-mauve tones which some other Sun Orchids have. This image appears to show it having strong veining on the sepals, but "in the flesh" those veins are less apparent.

Here is the same plant, showing most of the flowers on a single stem. The colour reproduction is quite accurate.
This is the "column" of this same plant, close up. You can see (up close) how it differs significantly from the other species displayed. I have given these photos a working title of "brilliant blue" until I get a proper identification on this plant. (Th. media is the best guide that I have come up with so far).

***Later note: I have since seen many excellent photos of Th. media on Colin Rowan's excellent Orchid reference site "retiredaussies.com" Go to his Orchid photos, click on the box marked Thelymitra - Sun Orchids, and scroll down to Th. media. I am now satisfied that my identification of this plant is correct.
This is another plant, which I believe to be an unspotted form of the "Spotted Sun Orchid" (Thelymitra ixioides). As may be noticed from the back of another flower (to the left) the outside of the flower is distinctively mauve. This does not show through when the flower is looked at directly. The "column" is distinctively hooded, with a black cap, a yellow line around the front of that "hood". The column itself is bluish, unlike both other species shown today which are white.
Here is the "column" of this plant.
Here is a not-so-good photo of Thelymitra ixiodes in its classic spotted form. While these two plants are different, and there are no spots on the one above, there is enough similarity in the column to lead me to believe that both are forms of Th. ixioides. I have not examined enough specimens of this species of plant (up close) to be able to say if we are looking at individual variations between two plants, or a genuine difference (between species).
Here is the very common Thelymitra pauciflora - the "Slender Sun Orchid". For a long time I believed that this plant was Thelymitra nuda, but "pauciflora" is a smaller flower, and paler, according to the descriptions in the books.This is a particularly clear image of the column of the same flower as above.
You'd have to say that Orchids are weird and wonderful plants, and the differences between the species are so small, you really need a magnifying lens, and or a really good "macro". But even then, the variations in locality, sunlight and just about everything else makes comparing these plants, from photographs, quite difficult. But they are so lovely, that one just feels compelled to try and solve the mysteries which they offer.

The fact that they tend to only open on really sunny days just adds pressure on the Orchid enthusiast to get out there and find them when you can.

2 comments:

Gaye from the Hunter said...

hi Denis,

I was delighted to view your local sun orchids, especially as I have not found any open flowers yet this season. Well done.

Gaye

Denis Wilson said...

Hi Gaye

Sun Orchids are lovely things.
A bit fussy re flowering, and location. There are many places I go where I simply do not find them. But then, sometimes you just walk into patches where they are everywhere. Many of the smaller ones open only for a short time, if at all.

Down this way they seem to like open areas, such as slashed roadside verges, and powerline easements.

But some of these are also in forested locations (on sandstone). As a genus, they are very wide spread, so they must be somewhere up there in the Hunter. You probably need to find less disturbed areas. I don't think they will have survived in farmland.

Down here, they seem to start flowering in Mid-October, but some are just coming into their prime now. Your seasons seem to be a little advanced from ours.

Keep looking. Their seed capsules last quite well (many are self-pollinating) so, if you find fertilised flowers, you at least know where to look next year (a little earlier). Greyish blue stems, usually about 12 inches high, sometimes taller. Usually a single strap-like leaf, but it looks grassy, so very hard to spot without the flower.

Cheers

Denis