Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Wednesday, January 23, 2008

The tiny "Wasp Orchids" have started to flower.

Yesterday I found the first of the "Wasp Orchids" in flower. These were found growing in the tall Eucalypt forests on sandstone, in East Kangaloon. These are the first of the summer and autumn flowering species of a large group of tiny Ground Orchids. This one is apparently Chiloglottis reflexa the "Short-clubbed Wasp Orchid". Don't blame me for the awkward name. This is the first time I have been able to correctly identify this species, although I thought that I had found it last year. I had to correct that report, with the help of some other experts, including Gaye from the Hunter.

Last year, I found another species, (Chiloglottis seminuda) which carries the even more awkward name of Turtle Orchid, because of an apparent resemblance
of the glands to the shape of the "neck" of a tortoise. While on the subject of related plants, this link will take you to a post which shows two of the related Spring flowering species (now classified as being in the Myrmechila genus). Those plants are now called "Ant Orchids". They have slight differences in the way the lateral sepals are held flatter and wider spread, not curved down under the flower, as in these summer-flowering genus. There are slight differences in the calli (glands) as well - some have a double tip on the "head" (resembling "bug eyes" of an ant). I kid you not.
As you can see, these little Orchids have paired leaves (often slightly crinkled on the edges) which lie almost flat on the ground, in the natural leaf litter. The flowers are on a stem approximately 4 inches (approx. 1o cm) high. Their colours are reddish on a green background. Their camouflage against the red-brown leaves is nearly perfect. The leaves are easy enough to see, but often there will be a large colony of plants, growing together, but relatively few might actually bear flowers in any season. So, even when surrounded by lots of these little plants, you have to really look hard to find the flowers. When you do, the details of these tiny flowers makes the effort well worthwhile.
I find these tiny Orchids terribly hard to distinguish - one from the other. I appreciate the opportunity to consult with Alan Stephenson of the Australasian Native Orchid Society.

These Wasp Orchid flowers consist of a large almost flat tongue ("Labellum") which lies underneath the upright column, which is supported (or protected) by the "dorsal sepal". The large yellow blob (on the tip of the column) is where the pollen (pollinia) and the female organ are both located. In the photo above, note that the glands (or calli) extend down over nearly all of the labellum. That, and the overall shape of the labellum, and the length of the lateral sepals, distinguish this species from C. seminuda.

As indicated by their name (Wasp Orchids), these Orchids are pollinated by small male wasps (Thynnine Wasps)
of the Neozeleboria genus) in a process known as "pseudo-copulation". This term describes what happens when the male wasp is seduced by the odour emitted by the plant, and apparently believes the plant to be a female wasp, and it attempts to copulate with the flower (as if it were a real female wasp). (Photos are available on this linked site - scroll down till you come to photos of Chiloglottis trapeziformis - a closely related species to this one - being pollinated by male wasps).The mystery of this process is being worked on by advanced studies in molecular biology, isolating the chemicals the plants use to produce a scent resembling the pheromone produced by the female wasps. I have slightly "lightened" the background to this photo so (if you click on the image to enlarge it) you can make out the heart-shaped gland (callus) of the main scent organ on the labellum of this Orchid. These structures (in total) are referred to these days as a "pseudo-insect" - which is fair enough if you think about it.

What a complex and bizarre world we live in. And we humans delude ourselves that we are running the place. We have only just worked out what is going on here - but how far are we away from being able to make such wonderful "constructs" as false insects, which not only resemble, but smell like, female insects? But between themselves, plants and insects have collaborated to do just that (or is it a battle by the Orchids to outsmart the wasps?). Either way, how many millions of years might that have taken?

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