Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Saturday, June 25, 2011

Corybas (Corysanthes) Orchids at Thirlmere and Jervis Bay

I wish to show you some Orchids I photographed yesterday at Thirlmere Lakes National Park.

Before showing you the Orchids, though, I must show this photo. It is a composite of a snap I took yesterday, and one that a friend of mine, Angela, took of a family picnic at Thirlmere Lakes in early 1993 (dated by the age of the children).
You need to click on the image to enlarge it. The point of comparison is that what once was a stone wall at the lake edge, is now a wall some 75 metres distant from the Lake. There are Wattles and other shrubs, about 5 metres tall, growing in the dry sand where the lake has receded. Its level has dropped approximately 20 metres. This is a national disgrace.

However, the area is still providing good Orchid habitat. These are Corysanthes fimbriata (formerly Corybas). The Corybas group are known generally as "Helmet Orchids" for reasons which will become apparent as you read on.

Funny little things, they resemble grapes dropped on the forest floor. They are about that size too, 

These were in the wettest part of the Thirlmere Lakes NP, close to the Blue Gum Creek section (about as far as one can go, except on foot). Technically, at this point one is in the Nattai National Park, part of the Blue Mountains World Heritage Area. In reality, we are still within the Thirlmere area - but there is a definite habitat change in this "far end" of the park. These Orchids were growing in deep leaf litter, in a wet gully, under tall Eucalypts, with some rainforest trees around as well.
Corysanthes fimbriata - face on.
Corysanthes fimbriata -note speckled hood, and fringe visible
Corysanthes fimbriata - viewed just off to the side

Needless to say, everything about the Corybas tribe of orchids involves lying down on the forest floor, to get any decent sort of shots. Fortunately the forest was dry, and the Leeches were all asleep (as befits their Winter Solstice mode), I would hate to do this in summer.

For comparison, here are some related plants, seen at Jervis Bay the week before.

The two sites are similar in one respect. Both are within Sandstone habitats, with deep grey sandy soil. The Jervis Bay site (for the following flowers) is coastal, south from Nowra, the Thirlmere Lakes site is in the heart of the southern "Sydney Basin", close to the Warragamba catchment (see linked "Location" map at the very end of this post - in the red Blogger footnotes).

You can see the Corybas family resemblance. A rounded leaf, flat on the ground, with a funny little hooded flower on a very short stem. Unlike some Corybas species, the flowers of both today's species are open to the outside world, because they are angled back, leaving easy access for pollinators.

These plants are Corysanthes pruinosa
Corysanthes pruinosa - seen from the rear top view.
Note the silvery grey tops of the flowers. whereas the previous ones were dark red and spotty, and very dark inside the flower. Both are heavily fringed around the outside edge of the flower (lower lip).
Corysanthes pruinosa - my best front on view

Corysanthes pruinosa - looking like little spotted "Marbles" on the ground. 

The trick with these plants is to look for their leaves - on the ground. Find them, and then look closely for the flowers. See one, you might realise there are many around.

Unfortunately, my flash unit ran out of battery power at this point and it was way too far to walk back to the car to get spares. So this is the best I can offer.

You'll get the point, however.

I have called these the "Three Wise Monkey" Orchids.
Three Wise Monkey Orchids - Corybas pruinosa.
Perfect grouping.
Completely natural.


mick said...

Very disturbing photos of the lakes and the way the water has dropped over the years. When will we learn that we don't have unlimited supplies of water in this country?!
The orchids are lovely. I am hoping that sometime my knees will be strong enough for me to go wandering around in the bush up here and I can look for orchids up this way.

Denis Wilson said...

Hi Mick
You might not have to walk far, if you get into the right habitat. Probably the Wallum area, near you.
These were both in deep sand, in areas under Eucalypts, the coastal ones were near lots of Cycads or "Burrawangs".
Ideally, you need a local plant group to show you firstly.
Then just keep your eyes out in suitable habitat.
They have one advantage over waders - they don't fly away if you get too close.
Hope your knees are improving.

Denis Wilson said...

Oh, and re the Water level, you are exactly right.
Guess what - there is a coal mine not far away.
DId it cause the levels to drop - we are asking for a proper inquiry. The MIne says they have not gone close enough to cause problems - its the fault of the drought.
Remember that one? It broke in this region 3 years ago. The lake levels are still dropping, and the mine is apparently pumping out 4 megalitres a day from its mine (to keep it workably dry).
Somehow it seems to be up to us to prove a connection.
There are trace element dyes which can be used., but I suspect the Department responsible does not want to allow such a test, because if it does prove a link, then it will reveal it was their fault in the first place for allowing the mine to go so close.