Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Friday, May 08, 2009

"Little Dumpies" found (at last) on Mt Gibraltar

I have been told for several years that the oddly-named "Little Dumpies" Orchids grow on The Gib. The name is not very flattering, but the flower itself is quite handsome, in a Greenhoodish kind of way. It is a relatively large flower, a little heavy in the front end of the "hood", but on a short stem. That is the reason for both the common name, and its scientific name Diplodium (or Pterostylis) truncata.

Here is the Botanical illustration from PlantNET, (from the linked site above).
Here is one growing amongst native grasses, in a fairly open position.
I have searched "The Gib" for these plants for two years, but my friends Colin and Mischa, came up from Victoria this week, and they had seen them here previously, and knew what to look for, and more importantly where and when to look for them. As with all Greenhoods, these plants go dormant, and become impossible to find. They are hard enough to find, even when in flower, because they tend to grow amongst grasses and other small plants in little rock crevices.

Note the heavy front end of the "hood" and the very fine "points" or "ears".
Colin's camera lens adds a sense of scale.
Fron the front end, you can see the blunt hood.
This specimen had nice "points" either side of the hood.

After Colin and Mischa's success in finding this Greenhood, I showed them some other leaves of other Orchids which I had been monitoring for some time, but without ever finding flowers on them. We scoured the patch of dense grass where the leaves were, and Colin found a flower. It turns out to be a large "Wasp Orchid" - Chiloglottis trilabra.

Botanical illustration courtesy of PlantNET (from the linked site above).Note the "glands" on the labellum going almost to the fine end of the Labellum
Also note the Labellum has a central "tip" which is clearly illustrated above.
Sorry the photo is so dark. I shall take a better image soon and replace these.
(Click to enlarge the images)
From the side, you can see the Lateral Sepals hang more or less straight down.
They are neither "reflexed" (as is Ch. reflexa)
nor bent forward underneath the flower, as is Ch. diphylla

I say large, compared to most of the other species of "Wasp Orchids" I have seen in the Southern Highlands, but of course, it is small compared to the Simpliglottis chlorantha, one of a related group of plants, which have now been split off from the Chiloglottis, (for very good reasons, I believe). Those larger flowered plants are better known as "bird orchids".


mick said...

Beautiful photos of the orchids again and thanks for the photos showing how it is growing among the grasses. I have an even greater appreciation for how you find these tiny plants.

Denis Wilson said...

Hi Mick
Well I did remember your request for "habitat" photos, at least on one of these plants.
Problem is I have to change lenses, and sometime I forget!
Indeed, it makes perfect sense to show at least the clump of grass, or the rock on which something is growing, if only to show the scale.

swampythings said...

I agree with Mick that the habitat photos certainly put the orchids into perspective. Delightful photos Denis; I especially like the attractive form of the Chiloglottis. Is it a specific wasp which pollinates the flower?

Denis Wilson said...

Hi Barbara
Partly right, partly erroneous name.
They are pollinated by specific types of wasps, but supposedly not a specific wasp species per orchid species. That is a problem for the researchers, for there seems to be little "cross pollination", which might be expected if the wasps are not "selective".
Re naming, the first group of these plants were named as "Ant Orchids" because the "glands" on the labellum were thought to resemble an ant.
In truth it is much more complicated than that - for there is a lot of study of their "pseudo-copulation" by male wasps, which "assume the position" with the flowers, on the "Gland of the Orchid" and then accidentally bump their head or back against the pollinia of the Orchid's column and get the sticky pollen grains stuck on their back or head.
There are many papers written about this, with photosDenis