Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Friday, November 19, 2010

Potato Orchids teach me about Gondwana

Several weeks ago, Colin and Mischa, from Victoria, came up here for the ANOS annual Spring tour of the Southern Highlands. During their visit Mischa reported seeing buds of Potato Orchids in a particular location. Then several days ago, Alan Stephenson sent me an email asking about Potato Orchids. So putting 2 and 2 together, I decided I had to go back and find Mischa's budding Potato Orchids. There is a hidden sub-plot to this, which I would rather not go into. Sorry Mick, but NO HABITAT photos this time. Suffice to say, here are some photos.
For those not familiar with Potato Orchids, they do not look much like conventional Orchids. That's a joke folks - as you would realise by now, "there ain't no such thing"!

These plants have dark brown stems and brownish flowers. Their leaves are reduced to small stem bracts. They lack chlorophyll and survive in a symbiotic relationship with a mycorrhizal fungus. They do not use photosynthesis for energy (food) production. That's why they do not bother to produce green leaves or stems. The name comes from a large rootless rhizome. Strange plants, but not alone in the weird and wonderful world of Orchids. Hyacinth Orchids are another local Orchid with a similar lifestyle.
There are a number of other tropical Orchids which are similarly leafless.

This genus of plants is found in India, Malesia, Australia, New Zealand. It is largely a Gondwanan distribution, but excluding Africa or South America. That's all for now, folks, but I will come back to this distribution.

Lets concentrate on the flowers, for now.
The narrow brown stem is 75 cm tall.
Here is a single flower.
You can actually see the pathetic little "leaf"
just below the lower flower, on the left.
A little shrivelled brown bract.
In terms of identification, this is an important image.
The flower "perianth" tube is about 17mm long.
According to PlantNET, the perianth tube
of Gastrodia procera is 15–20 mm long
whereas for G.sesamoides the perianth tube is only 9–12 mm.
Here is a close-up of the flower.
Gastrodia procera.
The specific epithet means "tall".
This plant was only 75 cm high,
which is within the range of both local species.
So that measurement is inconclusive.
Here is the opening of the flower. PlanNET explains this structure thus: Sepals and lateral petals
fused for most of their length to form a 5-lobed tube.
The yellowish tip is the tip of the labellum which is "free"
(attached only at the base).
The white "lump" (barely visible) is the end of the column.
To get that angle I lifted up one flower, to peer into the narrow opening.

In the interests of science I decided to collect one flower, to dissect it.
This is the "column" of the flower.
It is within the lower half of the flower.
In nature, as you have seen above
the "labellum" is above the column.
So, in nature, it lies "upside down"
You need to understand that the functional parts of the labellum
face the column.
So, this is the labellum turned over so you can see its "bits".
If you go back two images (above) you will realise that the yellow tip
you see is the end of this structure,
but in nature, it lies "face down",
so that the organs are facing the column.
Click to enlarge the image to see the details.
There are ridges, and the edges of the labellum are curled up.
There is a mass of yellow dust, which is referred to as "pseudo-pollen".

If your brain is hurting, just blame the "evolutionists"
Charles Darwin and more recently Richard Dawkins.
Dawkins is famous for his argument for the "Blind Watchmaker".
Prior to those guys we could simply "blame God"
for the existence for such confusing biology.
The good thing about that was
we felt no need to try to "understand" anything.

Sorry, but that does not work for me.
So, we struggle on, trying to make sense of it all.

Or else you can simply marvel at the complexity of Nature.
That works for me.

The reality is that we simply cannot get our heads around
the endless permutations and computations
possible over
some 150 million years
the break-up of the ancient proto-continent of Gondwana.

Source: Animation of Gondwanan break-up

It is generally acknowledged that Australia
has been an independent continent for about 80 million years.
So, with their current distribution, these plants,
or their progenitors

must have been around for much longer than that.

My mind cannot "contain" the evolutionary possibilities
over such vast eras of time.
But when I look at a Potato Orchid,
and ask how long it took for these weird plants to develop;
then, and only then, can I start to get my head around it all.

So, from little things we can learn something huge.


mick said...

Thanks Denis for another very interesting post. Thanks also for including lots of links - such as the one for "malesia' - a new term for me. I like the idea of "the complexity of nature'.

Denis Wilson said...

Thanks Mick
Glad you checked out "Malesia". It looks like a misprint, but it is specific bio-geographical descriptor.
Glad you followed me right through to the punchline.

Anonymous said...

Another wonderful and informative post Denis if not a tad philosophical. Orchids just keep on astounding us all with their intricacies.

Le Loup said...

Very good, I find this sort of thing facinating.
Though I had hoped you had found an edible plant!!! My special interest, but difficult to find anything for the New England area.

Denis Wilson said...

Hi Allen
Sorry if I overdid the philosophising.
Orchids do that to me. Such complex organisms.

Denis Wilson said...

Hi Le Loup
I believe the roots may have been consumed by Aborigines.
Les Robinson "Native Plants of Sydney" says they were, in Victoria and Tasmania.
He also quotes Daniel Bunce as having eaten them with Aborigines in the Dandenongs (Vic) and said they were "plentiful, large and well flavoured". Others report the flavour as "like Beetroot, but watery and insipid".
Conclusion, Bunce must have been very hungry.
But it must be a possibility, for people have survived the experience to report upon it.
So - there is a reason for the common name.
Best of luck