Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis
Showing posts with label Pseudo-copulation. Show all posts
Showing posts with label Pseudo-copulation. Show all posts

Sunday, January 08, 2012

Cryptostylis erecta (the Bonnet Orchid, or Tartan Orchid)

Cryptostylis erecta is a Tongue Orchid, but it is better known as the "Bonnet Orchid", or the "Tartan Orchid".
It tends to grow in coastal areas, but is known to occur in the Blue Mountains as well. But when I went out with Alan Stephenson the other day, to Leebold Hill (Cambewarra Range Nature Reserve) above Kangaroo Valley, I  said to Alan that I was hoping to find the Bonnet Orchid. It may occur in my immediate area of Robertson/Kangaloon/Fitzroy Falls, but I do not know of it growing there. Hence my interest in looking for it, on the wonderful high ridge above Cambewarra, and Kangaroo Valley. The habitat is similar to my local sandstone plateau areas, but it is warmer and wetter over there. The altitude is similar, but the Shoalhaven Valley region has a climate all of its own.

One can see why it earns both common names.
Bonnet Orchid, for the shape,
and Tartan Orchid for the colour and patterns.
Bonnet Orchid Cryptostylis erecta


Here it is, as I first found it.
It is growing in moist mossy soil, amongst grasses and rushes
over a shallow rock shelf (exposed rocks in background).
Bonnet Orchid Cryptostylis erecta

A closer view, to show the shape of the flowers.
Bonnet Orchid Cryptostylis erecta
Here is another close-up of the flower.
Add caption
It is appropriate to mention that this species is the main one featured in that Video I linked to last week, about "sexual deception" of Wasps by Orchids. Video by Macquarie University people (as named in the Video credits). That previous post was primarily about a related plant Cryptostylis subulata

And just for the record, the botanical illustration on the PlantNET site, for this species, Cryptostylis erecta actually illustrates the pollination process in detail.
Click on image to see in full size. 
Note the wasp pollinating the top-right flower, 
and the "reproductive organs" of the flower drawn in detail.

Botanical illustration for Cryptostylis erecta (courtesy of PlantNET)

Saturday, December 31, 2011

Cryptostylis subulata - "Large Tongue Orchid" in flower now.

It is very hard to say I have a "favourite Orchid", but Cryptostylis subulata goes very close to being that.

It was one of the first local Orchids I found and identified when I first moved to Robertson, so, it has precedence, if nothing more. Mind you, it is closely followed by the Flying Duck Orchid, which was the first Orchid I ever featured on this Blog. And there was a nice one there just yesterday. So that other species still rates pretty highly as far as I am concerned.

The first thing I ever learnt about this Orchid was its "wrong name" - Cow Orchid. Like all good "bad names" it tended to stick, because the idea of the long protruding "muzzle" and the two "horns" sticking back from the supposed cow head was a compelling mental image for me.
Cryptostylis subulata - Large Tongue Orchid - looking a bit like a cow's head
Having ruined this Orchid's name for you, I shall now try to recover my botanical purity, and give you some of the finer details of this strange Orchid, its growth habits and its pollination requirements and its deception techniques.

Firstly the leaf of this Orchid remains visible most of the year (unlike many Orchids). This gives one a sporting chance of finding it, and remembering where to go looking for it again, in flowering season. (From now till March in the Southern Highlands - earlier in the coastal areas). 

The leaf is quite tall - as much as 30 cm in some cases. And importantly, it has a clear green back (of the leaf), not burgundy-red like its local cousin, Cryptostylis leptochila. The leaf of this species is elongated, whereas Cr. leptochila tends to be ovate in shape.

Ok - so that is what to look for during the off-season.
Green back to the leaf of Cryptostylis subulata

When the plants are in flower, this is what you hope to find.
Cryptostylis subulata with four flowers (one out of frame)
Here is the flower up close.
(refer back to the previous image, 
to check the angle at which the flowers hang).
For photographic purposes, it works best to tilt the stem
during the shoot (or tilt the camera).
Note the stem is on the lower left, and is leaning diagonally.
In fact the stem is normally vertical, (but not always).
Cryptostylis subulata - the Large Tongue Orchid seen from a low angle.
And here is a hint to its "special features"
This flower has been knocked over by an animal, presumably.
I swear I did not push it over, in this case, just to "get the shot".
You can just see the dark strip of glands underneath the flower.
Those glands produce a special scent.
Underneath view of Cryptostylis subulata shows scent glands.
Those glands are the key to its reputation
as a "deceptive" plant.
It produces scents which mimic the pheromones
of a female wasp.
That "trick" dupes the male wasp 
into attempting to mate with the Orchid.
This process used be referred to as "pseudo-copulation"
but that term seems to be going out of favour.

about the complex relationship 
between this Orchid and a wasp on her Blog
when one of these Orchids came up in her backyard, in Sydney.

Here are three links to images which show the wasp attempting
to mate with the flower 
(just in case you do not believe the story.).
 Here is my best attempt at photographing the glands 
underneath the flower.
(That is a reference to the fact that I am still
in "recovery" from a Hip Replacement Operation
and my mobility is extremely limited).

Unlike the related Cryptostylis lepochila
this flower hangs down, 
which means the sexual organs of this flower 
(the white bit just visible)
are at the "top"*** of the flower
That means the wasp has to approach
the flower upside down too.
Black glands underneath the flower of Cryptostylis subulata.
 The white part of the flower 
at the 'top right of the image"
is where the Orchid's sexual organs
(the Column and the pollinia) are located.

Margaret Morgan's colleagues at Macquarie University 
have even captured the whole deal on a short video (1 min, 10 seconds).
The first example is with another Tongue Orchid species, 
Cryptostylis erecta.
But in the middle (about 25 seconds into the clip), 
there is one brief sequence involving this species too.
You will notice that the Wasp 
has to hang upside down - on this species -
for reasons I have already explained.
But it is good to see the "process" in real time imagery.


 *** In Botanical terminology, the part of the flower closest to the stem is the "base", regardless of the angle at which the flower is pointing. But for this purpose, I am referring to the part of the flower which is highest as the "top".


See you all next year!

Monday, November 23, 2009

More odd little things which happen around Robertson

My very first post on this Blog involved the Flying Duck Orchid, (Caleana major). It was called "Odd little things which grow around Robertson".

Two weeks ago, at the end of the ANOS (Illawarra Branch) field trip, several of us found this little Orchid. If you look at the "head" of the flower, and see the "duck head" - then the mystery of the name will reveal itself.
Click on the image to enlarge it.
Not only was the Orchid in flower., but there was a Mosquito attempting to pollinate the flower - hence the slight variant in title from the original Blog Posting.

In fact the Mozzie was too small to trigger the labellum of the Orchid (in this case the "head of the duck") to snap closed. You can see the pollinia are still in place, at the very base of the flower. But clearly the Mozzie had the "right idea".
Click on the photo to see the Mosquito and the flower parts - in detail
For those of you not familiar with pollination in many of Australian Orchids, the plants have evolved a system of emitting highly specialised scents which mimic the pheromones produced by certain female insects. This drives male insects (of the right species) into a sexual frenzy, and the insects attempt to "mate" with the flower. This process is called "pseudo-copulation". It is well reported, in the world of Orchids and insects.

This link will take you to other photos of this species, one with a flower spider in a web spun across the open section of the flower - obviously waiting for an insect such as this one, to arrive.

Saturday, January 10, 2009

Large Tongue Orchid

This plant is one of the first Orchids I found after I moved to Robertson, and got into the habit of scouring the surrounding countryside, especially on the sandstone plateaux which subtend the basalt hills of Robertson. Although I had often found leaves of this plant, I had not seen flowers for the last 4 years. I did see one very fine specimen when south from Nowra with Alan Stephenson ten days ago. But none in my own "backyard".
Consequently, when Colin and Mischa turned up here last week, and commented, in an almost off-handed manner that they had stopped off on the way over to take some photos of Cryptostylis subulata - I was keen to find out where they were. My amateur Orchid hunter's "professional pride" was at stake, if you know what I mean.

Mischa told me where she had first seen these plants, along the Belmore Falls Road, and as I knew the area well, I was confident that I could find them from her descriptions. Wrong!

The next day I rang Mischa and tried to obtain some more explicit instructions, and went back again. Still no luck!

Oh well, why not just look for different plants in the same general area?
At last, some success, along the side of the road near Missingham Lookout, near Belmore Falls.

Once I had found several of these Tongue Orchids, I was then able to go back to the area Mischa had told me about, and sure enough, I was able to find them. Of course they were there all the time, but it is just a case of knowing where to look. I had been looking in the open areas, beside the road, whereas the plants were growing a few metres back from the road, and growing amongst rushes and other dense ground covering plants.The flower structure of this Tongue Orchid is quite bizarre (but all the others are, so why not this species?).

The main structure one sees is the Labellum. These Orchids are non-resupinate, which means the Labellum is on top of the column (not forming a "cup" under the as many popular "slippper orchids" do). The labellum, in this species hangs out at about 45 degrees to the ground. In this regard it is quite different from the closely related Cryptostylis hunteriana, which holds the labellum vertically. I wrote about that plant last week.

The next thing one notices about this flower is the odd "bump" underneath the labellum, clearly visible from the side. It is called a "callus".In fact it is a prominent part of the sexual attraction process by which this flower achieves pollination. The "callus" is in fact a two-part protrusion, (a gland no doubt) by which the flower produces chemicals to attract wasps, in a process now described as sexual deception. The odours produced mimic the pheremones produced by females of certain species of wasps. The male wasps engage in what is called "pseudo-copulation". The male wasps get confused, (poor dears). One might think of these flowers as the plant equivalent of a "blow-up doll".
In this angle (from underneath the flower) you can
see the "double bump" of the callus I have been talking about
In the next image, you can actually see the entire area of the "callus", which has a relatively long series of glands, (shiny, dark red glands) leading up to the "double bump" part. You can also see clearly the yellow dot, where the column of the flower is located. That is where the pollinia are located, and where the receptive part of the flower is. This photo has been taken from underneath the flower. One does not see this part, unless you look very closely indeed.Here is another view from low down, and it shows nicely the parallel lines of the glands which are all part of the "callus" structure of the flower. Click to enlarge the image.In this last image I want to show why this plant earns the "nick-name" Cow Orchid. The lateral sepals in this flower (as in all the local Tongue Orchids) are reduced to thin, rolled protrusions. In this case you can see how some people say they resemble the horns of a cow. But to get the full picture, you ought see how the labellum has rolled back edges (revolute), and they form a kind of protruding "lip", which could be thought to resemble the snout of a cow's head. OK, you have to squint a bit, and use your imagination, but I did not invent the name. It is safer to stick with the name Large Tongue Orchid.

I have a sentimental attachment to this Orchid, as I mentioned and I am glad to have seeen it again, this season. Thanks to Colin and Mischa for having told me it was flowering this year.

Sunday, July 06, 2008

Pterostylis hildae starting to flower

Pterostylis hildae (Rainforest Greenhood) is just starting to flower at Macquarie Pass. Colin will be pleased - he has asked me to keep a look out for them (which he knows I would have been doing anyway).

Here are two shots of the side of the flower. It is a small Greenhood, growing to less than 6 inches (most were smaller than that).Mature flowers have a brownish tinge on the "nose" of the hood.The labellum has an interesting shape, resembling a mini surfboard, complete with a nice brown stripe down the middle. Very cute detailing.I also saw the first of the winter/spring flowering "Ant Orchids" - which these days are classed as members of the genus Myrmechila. The more common "Ant Orchids" or "Wasp Orchids" in this district are the autumn flowered species, which are classed as Chiloglottis. All of these related plants are still classed as members of the genus Chiloglottis in the minds of the people who run the PlantNET website at the RBG Sydney - even though there are very good reasons to class these plants as separate genera, especially the much larger-flowered Bird Orchids (now called Simpliglottis). Related plants, yes. Same genus - I don't think so. I go with Jones and Clements.

This plant is Myrmechila (Chiloglottis) formicifera (the "Ant Orchid" - in English and Latin names).

From the front, the column is a clean green/yellow colour, whereas the basically similar Chiloglottis seminuda (an autumn flowerer) has strong lines of red across the flat front edge of the green "column". The "pseudo-insect" has a double-headed shape, by which I mean it is like a bug-eyed insect. You can make out clearly the protrusion at the far end of the "pseudo-insect's head". In fact it protrudes to the left and the right. Some of the autumn-flowered species have heart-shaped "glands". This one clearly is not like that.

The secondary set of glands, smaller little bobbles of "jelly" go right to the bottom of the labellum (that is the diamond-shaped blade which is protruding at the front of the flower). Also, the lateral sepals are held shallowly, and are widely divergent (like two narrow blades, on the left and right). They are reflecting the light from the flash, and so they stand out, in this image. That is a considerable difference from the autumn-flowered Chiloglottis species which I have photographed, where the lateral sepals are held very low under the labellum, either reflexed or bent forward under the labellum, but not spread wide, like in this flower.
Here you may observe the gap between the major gland (the "pseudo-insect") and the smaller glands which extend all the way down to the tip of the diamond-shaped labellum. The "pseudo-insect" not only resembles an Ant (in our eyes), but apparently it emits scents which mimic the scents of female wasps, and so, it attracts male wasps which attempt to copulate with the flower. Thus does the flower achieve its pollination. This is called "pseudo-copulation". All of this is now well documented, and it is not my imagination running away with me.I would have to say that I went looking in a place where I had previously been shown leaves of these Orchids, and found some leaves straight away. I stared and stared and it was only when I knelt down to get a really close look that I found the first flower. It was about 3 inches from my hand. What I am trying to say is these tiny, dark flowers are really hard to see, even when you know they are there - right in front of you.

Because these small flowers are so well camouflaged, it is no surprise, therefore, that they are famous for their reliance upon scent glands in order to attract pollinators. In fact, it is an interesting area of science which brings together entomologists (who identify the insects), botanists and molecular biologists, who identify the chemicals which the plants use to attract the pollinating insects.

Monday, February 04, 2008

Chiloglottis Orchids are out in force, now.

This is very satisfying to report. Three different species of Chiloglottis Orchids in a single day's outing. I went out with Chris, a fellow member of the Illawarra branch of the Australasian Native Orchid Society. Chris is an expert photographer, and he has an excellent website, which you may visit here. I have also linked to Chris's Orchid gallery, via my Aussie Orchid sites links on the right.

These little Orchids are known in general terms as "Wasp Orchids" (a reference to their main pollinating insects). Previously they were known as "Ant Orchids", or even "Bird Orchids" as the first species described held their flower open to the sky, and supposedly resembled the mouth of a young bird, begging for food. Under new taxonomic revisions, both those names are now reserved for separate groups of related plants.
This first species is new for me. Chiloglottis sylvestris. I first found these plants this time last year, just after the last flower had been pollinated. However, I could not conclusively identify it then. These flowers close over, once they have been successfully pollinated, making photography of the distinguishing features impossible. The labellum (the lip, with the insect-shaped gland on it) rises up to close over the "column", protecting it from further disturbance or interference from insects.

In case you are wondering: "How does the plant know it has been pollinated?" The answer is that hormonal signals are sent from the ovary of the plant, causing the plant to enter a different stage of its development. That fact is a timely reminder that plants are indeed sentient organisms. That simple sentence would have been regarded as heretical in earlier centuries - and might have had me burnt at the stake. But I stand by that statement.

Incidentally, that argument is further supported by the amazingly complex relationship between these plants and male insects (mostly wasps) which pollinate them by pseudo-copulation. That topic has been discussed before, here, and back in 2005, here.

This flower has been photographed from over the top of the flower, to show the positioning of the "clubs" (the lateral sepals). Also, it shows the main gland as not being divided, (as a distinguishing characteristic from the other two species discussed below). The slight "V" shape of the labellum is an optical illusion, because of the angle of this photo. The upper photograph shows the true shape of the labellum.Anyway, last year I worked out what this plant might be, but I could not be sure, at the time - for the reasons stated. The first distinguishing feature is the habitat where these plants are growing. It is entirely different from the habitats where I have seen related species growing. I have been able to confirm the identity from the reddish colour of the flowers, the shape of the "pseudo-insect" (with an undivided "head"), and also the lack of reflexing of the "clubs". The short height of the stems (little more than two inches (50mm) and small size of the flowers is also a "fit" for this species. These are really tiny "Wasp Orchids" (and the other ones are not large).

These plants are growing in heavy shade, under dense cover of Tea Trees and Melaleuca scrub, in a muddy creek bed. The area is wet most of the year, and especially at flowering season (now - when it is raining constantly outside, as I write this post). These plants may well be under-water today. These plants are in the general Belmore Falls area, about 5Km south of Robertson. This plant is known to be at its southern limit of its distribution at Robertson.

The next species is a plant which I identified last year - the appallingly named "Turtle Orchid" (because an early botanist thought that the tiny "glands" on the labellum looked vaguely like a turtle, with its long neck protruding). The name Chiloglottis seminuda, is a reference to the labellum having a bare area at the lower end. (Other species share that feature, but it was named to distinguish it from others which have a larger area of the labellum covered with glands). This second species was growing in heavy black soil, derived from Wianamatta shale, over a sandstone rock base. The forest cover is tall Eucalypt forest, with mixed Proteaceous shrubbery - Waratah country.

Here are new photographs of Chiloglottis reflexa, which I reported on two weeks ago - it was a new species (for me) at the time. These specimens are probably more diagnostic. Here you can see the divided "head" of the pseudo-insect (gland). It looks almost heart shaped. The lateral sepals, (the "clubs") spread widely, and then curve right down and under the flower and almost curl back up again. In profile, you can see how "reflexed" those clubs really are - almost touching back up to the top. That feature is how this species earns its name. The fairly large bare area of the labellum of this particular plant is not typical. Others in the same cluster of plants had much larger areas of cover of glands over the labellum. But the reflexed "clubs" are diagnostic. These just happened to be the clearest photographs I was able to get yesterday. The first flower in the previous posting (click here) has better gland development. It is the same species, growing in the same colony of plants as these plants shown today. This third species was growing in sandier soil than the second one, and less than one kilometre away from the location of the second species. While the forest cover in both places is similar, it is slightly more open, and the soil is definitely drier and sandier, as the ground is raised, being over a small sandstone outcrop. Species two and three are growing in East Kangaloon, about 5 Km north of Robertson.

Here are three images together in an attempt to give you the comparative features of the structures of the glands of these 3 species. The identification of these species does not hinge solely on the gland structures, but it is a good place to start. Unfortunately, at this level of cropping there is a great distortion of detail introduced into the image. But it is worth doing, for educational purposes, if somewhat disappointing, artistically. Click on this triple image to blow it up to a larger size, to allow a better look at the structures of these glands.

Wednesday, December 05, 2007

More Orchids (and Trigger Plants) in Kangaloon.

I am pleased to report that the late flowering perennials (small native plants which are "herbaceous", but persistent, across a number of seasons) which grow along Tourist Road, Kangaloon, have survived the slashing which was given them by the SCA's contractors on 31 October 2007.
Trigger Plant
The main flowers down there, at present are Trigger Plants, Stylidium graminifolium (not Stylidium lineare as I first thought) These cheerful looking plants are waving their pink flowers around on stems about 30 cm high.
(*** Possibly - I have not done a close study, I am sorry.)

With the grass having been slashed recently, of course they stand out, and are clearly visible as one drives along Tourist Road.Some Hyacinth Orchids (Dipodium punctatum*** and *** ***) which were still dormant at the time of the slashing along Tourist Road, Kangaloon, have survived.Many which were already growing then, will have been beheaded - but some have survived. The numbers of Hyacinth Orchids in flower this year is greatly reduced from last year.

These plants have a protruding labellum, (front and centre) which acts as a landing platform for insects, seeking to find the column, which is inside the tube, below the yellow spot, (underneath which the pollinia are located).
These plants grow from large underground tubers, and are hemi-parasitic, surviving by association with mycorrhizal fungi which in turn rely upon Eucalypt trees, close by. They have by-passed the need to produce their own food by photosynthesis, so this species has no true leaves, and no chlorophyll. Its only need to emerge above ground is to be pollinated, and to spread its masses of fine seed on the wind. It lives underground for approximately 10 months of the year. Given what the SCA does to them when they do emerge, that is a pretty clever strategy.

Both these pink flowers, are carried on narrow stems, and can cause some confusion as to what they are. Close examination shows the flowers are very different. Hyacinth Orchids are much larger flowers. This group of Hyacinth Orchids in the forest in Kangaloon is doing very well. Tall brown shoots just budding up.

*** I have corrected a previous incorrect identification of this flower as Dipodium punctatum. DJW 27.12.09
*** *** I have reverted to the original identification after an intensive check of all habitats of the Hyacinth Orchids in Kangaloon and Mount Alexander of which I know. These plants in this clump are definitely D. punctatum. Confirmed on 2 Jan 2010. DJW. I will publish the results of that investigation shortly, on this Blog. 2.1.10.
Trigger Plants have a square looking flower, and close examination reveals they hold out to one side a specialised "column" which is the so-called "trigger". This "column" carries both the anthers, (male organs) and the stigma (female, receptive part of the flower), although the different organs mature sequentially, so the "trigger" is functionally male, first, then, later, functions as the female part of the flower. This structure is well illustrated on the PlantNET site. The "trigger" is movement sensitive. It is on a deep red "handle", positioned on the side of the flower. That "handle" is flexible. There is a deep pink tube inside the ring of paler pink tufts, right at the centre of the flower. When an insect probes inside that narrow tube, (presumably to obtain some nectar) it "triggers" the little "hammer", (clearly visible at the left of the flower) which swings in, to bang an insect on the back while that insect is seeking to collect nectar from the flower. The insect ends up with a dob of pollen on its back, or alternatively, transfers a previously collected grain of pollen from another flower - transfers it (hopefully) to the new flower, thus completing the pollination process. It is possible for an observer to stimulate this reflex action, with a fine piece of grass, probed right inside the tube. The "trigger" will swing over, past the top of the flower. If you were an insect, you can see how the "hammer" would have hit you on the wings, or the top of your head. The plants re-set themselves after a short period of time, so the experiment does not harm the plant in any way.

To coin a bad pun, it is a "hit or miss process of pollination". But judging by the number of Trigger Plants growing on Tourist Road at present, they must be doing something right.

The other Orchid to begin flowering down in Kangaloon at present is the Small Tongue Orchid (Cryptostylis leptochila) There is one particular plant which I have been monitoring for some time. It was budding last week. It opened its first flowers yesterday (4 December). I did not have time to stop to get a new photo, so I will re-publish my favourite photo from last season. I have written previously about the bizarre process of pollination of these Orchids, by male wasps. It is called Pseudo-copulation. You can read about it in my post from 2005.

Thursday, September 13, 2007

How Orchids are pollinated.

Instead of doing a demonstration with tiny native Orchids, I took the opportunity of using some Florist's Orchids (Cymbidiums) which were at the CTC as a result of a local Artist, Tanya Petra Daniels, having had a "launch" event for her art exhibition "Mish Mash" there. These photographs are roughly "life size" so you can see what is going on.
These are the typical large flowered Orchids which we all know, and love. And I concluded, rightly, that I could demonstrate how pollen is exchanged from the plant to an insect (my finger, in this case).

I could not see the pollinia within the flower, but I knew roughly where they would be located. That is above the point where a large insect (presumably a bee, or maybe a wasp) would go to investigate the flower. They poke around inside the flower, and as they back out, they brush against the prominent cap at the top of the "column".
I pushed the tip of my finger into the centre of the flower, then drew it back slowly. As I did so, a cap on the top of the part of the flower (the column), acted as if it was hinged. It lifted from the lower side, and, in so doing, my finger came into contact with the pollinia which are located inside that cover.
These dual grains of pollen are stuck onto my finger, with a form of natural glue, which was remarkably effective. Has any scientist or technologist investigated what is the nature of the glue which Orchids produce? I wonder. It "set" instantly on my finger and was quite strong. Amazing stuff, really.
Here you can clearly see the dual grains of pollen. If you look at the tip of my finger, you can see the white glue substance on top of my fingernail (directly under the two yellow grains of pollen - the so called "pollinia".) That name is used, for Orchid pollen to distinguish it from normal plant pollen, which is usually a fine dust. Orchid pollen is packaged this way, so that it is stuck onto the back of an insect, which is meant to transfer it to another flower.
If you follow this link, it will take you to a truly remarkable series of photos which show insects being "stuck" or "dobbed" with Orchid pollen. In some cases the photos show insects already bearing Orchid pollen, sitting on other Orchid flowers, ready to accidentally pollinate those flowers. I say "accidentally", for the insects are not aware of their role as "couriers" for the precious Orchid pollen which is stuck onto them. The insect come to the Orchid flowers because they have been attracted by the scents produced by these native Australian Orchids. These scents make the insects believe that the plant is in fact a female insect (usually a wasp), and the male insects attempt to mate with the flower. This is the process known as "pseudo-copulation".
*****
According to an article which was published in the Sydney Morning Herald recently, there is another factor at play, other than scent. That is, the ultra-violet vision of insects. According to that article, we humans see the flowers and the insects as quite different. But, the reflected UV light from a flower of a specific Orchid species and the female wasp of the appropriate pollinating species, were examined through a spectrometer, and were found to be virtually identical. In other words, to a male wasp, the colours of the flower and of the female wasp make them appear identical. Strange, but true.
*****
And, while searching for the text of the above story, on the Net, I found this really interesting story, which says that a fossilised bee has been found (preserved in amber) with a dob of Orchid pollen on its back. The amber is able to be dated, and it shows that Orchids have been doing this trick for some 20 million years.

Furthermore, this discovery has allowed scientists to use DNA analysis on the Orchid pollen, to estimate how long it has taken Orchids to evolve to the huge divergence we see in the Orchids of today. The estimate is between 76 and 84 million years - far older than anyone had thought. Scientists have hypothesised that Orchids, being highly evolved (adapted to highly specific environments and also features of their life cycles, such as their complex relationships with insects), are relatively new in the plant kingdom.

Seemingly not. Rather, they appear to have been around since the days of T Rex. Makes sense, I guess this figure allows them an awful lot of time to have trained the insects to be their sex-slaves.

Orchids come right at the end of the formal plant classifications. That is because those classifications work as a kind of family tree, which start with the so-called primitive plants, and move through to more "modern" plants. That classification might have to be revised, based upon this finding.

What price a single piece of amber with Orchid pollen in it? This piece of scientific information is virtually priceless.

Monday, September 10, 2007

"Ant Orchids" are flowering here, now.

The troublesome little Ant Orchids, the leaves of which I have been observing everywhere around in the tall Eucalypt forests (on Sandstone) have started to flower.

This little thing is possibly Myrmechila trapeziformis (formerly classed in the genus Chiloglottis). The "labellum" is diamond shaped, and the glands are restricted to the "base" of the labellum (the part closest to the main part of the flower).
I say troublesome, because of the problems of identifying these little plants. This is the same specimen as above, and you can see that the front part of the labellum is more or less clear of glands. Compare this species with the "roughly similar" Chiloglottis seminuda, which has a different shaped labellum and is in the autumn-flowered group of these plants.
Did I say "identify"? I should firstly say "find"; and then again, "photograph".

Compare the gland structures of this next flower with the one above. The glands, (which are referred to by the Orchid specialists as a "pseudo-insect") extend down to the very tip of the labellum. These plants have developed a system of growing glands which physically resemble an insect, as well as mimicking the scent of the female insect (a wasp). This induces the male wasps to pollinate the flower, while attempting to mate with what the wasp believes is a female wasp, of its own species. In fact it is, of course, a flower. This process is known as "pseudo-copulation".

This species is almost certainly Myrmechila formicifera - the second name means "ant bearing" - in other words, the Orchid with an ant on its tongue (labellum).
The way they hide in the leaf litter is one thing. Then, their little flowers are very 3 dimensional, and need to be photographed from above (to see the extent of the glands ("calli") on the labellum, from the side to show the angle of the labellum (how "upright" it is held) and front on to show the position and the shape of the column and the dorsal sepal behind it. And with such a small flower, it is very hard to focus on them anyway, but doing it while lying on the ground, in 3 different positions, (and, on Macquarie Pass, checking oneself for leeches every time you get up off the ground) is more than most of us can bear.

Looking "over the shoulder" of the flower, you can compare this species with the second top photograph above, in which the glands are restricted to the top half of the labellum.

Saturday, July 07, 2007

The Nature of Orchids of Robertson.

I wish to acknowledge the inspiration and assistance of two Australian Orchid enthusiasts and inhabitants of the Internet. One is "Gaye from the Hunter", whose blog "Hunter Valley Backyard Nature" has featured a section on the biology of Orchids, which is well researched, with excellent "links" to other scientific papers.
The other is the owner of the excellent Website "banjorah.com"
That lady has excellent Orchid photos, plus a very useful section on her webpage, called "Orchid Facts" which has various illustrated photos of Orchids with their parts named. (That section works best if used with "Internet Explorer"). In several of my illustrations I have followed the lead set on her website.
Classic Orchid "parts"
illustrated (D. Jones ***)

Last Thursday I gave an illustrated talk to the Austalian Plants Society, Southern Highlands Branch, about Orchids of the Robertson area (Robertson and Kangaloon).

About 55 people braved the cold of Moss Vale to attend the talk, for which I was very grateful.




Stylised structure of
the symmetry of an
Orchid's flower.
I began the talk with some brief discussion (and illustrations) of the "parts" of an Orchid flower, as I know this is a bit of a block to most people. The strange names used by "Orchid people" confuse some plant enthusiasts.
I like to start my discussion from "first principles" of plant biology, where possible. In simplest terms, the sexual organs of the Orchid are combined within the central part of the flower. This is known as the "column". It includes the pollen-bearing organ (the male part) and the stigma (the female part) which most people never get to see, but which, of necessity, is of vital interest to insect pollinators. Usually the attraction comes from scent glands, although some Orchids (such as Potato Orchids) have evolved other attractions, (in that case "pseudo -pollen")
It is never that simple!
Here is a diagram of how the common "Ladies Fingers" Orchids have evolved differently from the classic structure. The red arrows indicate the variation of position from the "standard model" above.

I showed a collection of photos of 37 species of local Orchids. There were only two species of which I have photos, which I did not show.

I am hoping to add greatly to my "collection" of species over the coming winter and spring seasons.
Partly this is due to the fact that I now own David Jones's (***) wonderful Orchid book "Complete Guide to Native Orchids of Australia". This book is wonderfully detailed and is the best reference text which is currently available, for native Orchids of Australia.

Armed with this book, and a magnifying glass, I hope to make more sense of the Orchids which I will find. It has all the "new names" which the taxonomists have come up with, as they have reclassified the various types of Orchids. While I am not enamoured of "splitters" generally, some of the old Orchid genera, such as "Caladenia" which included the common "ladies fingers" types and also the elaborate "Spider Orchids" were desperately in need of revision. Similarly the Greenhoods and Sun Orchid groups.
Now for a real flower.
It is "Never That Simple"
Glossodia minor
(Click on photo to enlarge)
The "sepals" form the outer protective coating of the flower, when it is in "bud" stage. As the flower matures, and opens, they develop their characteristic shapes and colours, different for each species of Orchid.

This Glossodia flower differs from the sketched "Caladenia" type of flower (sketched above and photographed below) in that it does not have the Labellum as a dominant structure. It is there, just less dominant. It is in the classic position, underneath the "column".
The Labellum is a modified petal. Thus Orchids can be seen to have 3 sepals and 3 petals - one of which is usually, but not always, heavily modified. (Sun Orchids have almost exactly similar petals and sepals - without a characteristically shaped "labellum"). Thus they are more "regular" than most other Orchids.
The Glossodia flower is interesting in that it has two really obvious "calli" or glands (easily seen if you clicked on the photo).
Pale pink Petalochilus species.
If you click on this photo you will see that "Caladenia types" have rows of "calli" on their Labellum which act as something which David Attenborough (in his "Private Lives of Plants" TV documentary series) described as like "landing pads for insects".

This is a pale pink form of Petalochilus carnea (as far as I can work out).



It is "Never That Simple" (again).
Greenhood Orchid
seen from above.
They have
"special names" for
their parts too!
Greenhoods such as this Superb (or Cobra) Greenhood (Diplodium grandiflorum) have fused the two free Petals and the Dorsal Sepal into a "hood" structure. The "Labellum" (so dominant in "Slipper Orchids" for example) has become an internal structure, which is movement sensitive and motile. It senses an insect's presence, and snaps back into a closed position, to trap an insect pollinator, preventing its departure until it has been dobbed with the "Pollinia" - a sticky package of pollen which all Orchids produce.

Here is a side-on photo of the same species, which shows the erect "labellum" inside the flower. The shape of the Labellum, and whether or not it protrudes, is one of the diagnostic features of the Greenhood group of Orchids (many of which are not "green" by the way).

The front section of the flower is formed by the Lateral sepals, of which the lower sections are fused to form a structure called a "sinus", while the upper parts generally protrude to form the "points" (sometimes called "ears").


"Silhouette" of the Labellum
of the same Greenhood


Forgive me for one "art shot" - an almost accidental silhouette shot.
It happens to show well the raised Labellum of this Greenhood. I like the interesting visual effect, anyway.






Tall Greenhood with Labellum open
and then another shot when the labellum
has snapped closed.

The unfortunately named Bunochilus longifolium.
Perhaps I should not criticise this name, for the earlier name, Pterostylis longifolia never exactly tripped off the tongue.


This tall "Greenhood" does have quite long leaves along its stem, which make the plant quite readily identifiable, even when it is not in flower.

It is "Never That Simple"
- even less so, now!
This Small Tongue Orchid (Cryptostylis leptochila) is one of a group of Orchids which have reversed the "typical" structure, with the Labellum on top. In fact, according to the experts these Orchids are the "right way up". Apparently most "normal" Orchids actually twist as the flower matures, to put the Labellum underneath the Column. There are many genera of Orchids in Australia which are oriented in this way - "Leek Orchids", and "Duck Orchids" are two other groups amongst the local Orchids which are oriented that way.

Confused? Don't worry - we all are, a bit, at least. It takes time, but it is worth persevering with.
Chiloglottis reflexa
The complexity of Orchids always teases my sense of "wonder" - because of how complicated they have managed to become. I have only begun to scratch the surface of that discussion, here. For their evolutionary adaptation has taken them to great heights amongst plants - where some even have developed glandular modifications which physically resemble insects, as well as emitting appropriate odours to further complete the mimicry. This plant is in the group of Ant or Wasp Orchids. The structure resembles an ant or a female wingless wasp, but it is a structure of glands called "calli" on the Labellum of the Orchid. Calli is plural of "callus", meaning a swelling, or growth.

These Orchids then rely upon confusing male insects to such an extent that they attempt to mate with the flower, in the belief that it looks like, and apparently smells like, the appropriate female insect (mostly wasps). This process is called "pseudo-copulation", and is surely the ultimate in plant mimicry. How and why do they do it? Our imaginations can only guess at the answer.

I am not attracted to Richard Dawkins "Blind Watchmaker" model, but the main thing is our inability to imagine the possibilities which can arise over a length of time such as 65 million years, which is apparently the length of time since Australia apparently split from Gondwana. If we cannot "imagine" that time span, how can we imagine the possibilities of evolution which might have occurred within that time span?

Instead of finding it necessary to "understand" all of these issues, I prefer to enjoy the sense of "wonder" which is triggered by contemplating such tiny puzzles as these bizarre Orchid adaptations.