Bird Orchids are back!

I have posted about these little charmers previously, but I am going to write them up again, because they are special.

They are highly localised plants, occurring in an area just near Robertson, on the Budderoo Plateau.These Bird Orchids get their name from the manner
in which the flower is held high,
resembling the open beak of a small bird, begging for food.
There are a number of closely related species, in other areas.
This is the only one I have seen.

This Bird Orchid is known as the "Wollongong Bird Orchid", the Green Bird Orchid, or Simpliglottis chlorantha (or Chiloglottis chlorantha).

It is found here on the Budderoo Plateau, and further south to the Budawangs. There may be some records from the Blue Mountains.

Botanical Illustration courtesy of PlantNET

Although David Jones mentions this locality in his book as Knights Hill (approx 6 Kms away), that reference is quite misleading. Knights Hill is a basalt capped mountain, with tall, wet Eucalypt forest, whereas these plants grow on shallow, sandy, peaty soil over a shallow sandstone rock shelf. They grow amongst small "heath" vegetation. In fact, they are quite hard to find, because of their tendency to grow in and amongst these low shrubby plants. One can clearly see Knights Hill from where these plants grow, but that's about all one can say in favour of that "location" note. Budderoo Plateau would have been a much better location descriptor.

You could hardly get more different habitats than Knights Hill (with a 30 metre canopy of Eucalypts and Sassafras), and where these plants are, growing under and amongst heath plants scarcely 30cm high.

Here is a close up of the Labellum.

The botanical description says: "Labellum cordate, 12–13 mm long, 9–12 mm wide, with c. 12 linear to terete, erect or curved calli on the basal two-thirds, the largest c. 3.5 mm long."

I prefer to describe the pale green, almost "luminous" green glands (calli) towards the tip of the labellum as looking like blobs of soft jelly. There are two large ones, and two small upright ones, flanking them. Behind the green glands are a series of upright glands, which look like they are made of red jelly. From the front-on view, these structures vaguely resemble chess pieces in some bizarre Chess Set, perhaps from an Alice in Wonderland story.

In the typical positioning of Chiloglottis Orchids, the column is held high, but directly above the labellum, ready to dob the sticky pollen grains on the back of a wasp which tries to mate with the flower (which smells like the female wasp).

Interestingly, the Labellum although looking quite stiff, is actually very lightly "hinged" and the labellums *** of these flowers were trembling in the warm breeze today.

This specimen has given its pollen away already,
to an unsuspecting wasp. one assumes. The yellow housing for the pollen is now empty,
and the receptive female part of the flower is clearly exposed.

Compare this flower (complete with pollen grains still present)
with the empty one, above.
This flower has an ant crawling across it, (click to enlarge image)
but the ant is not the suitable pollinator for these flowers.

*** Please forgive the use of the word "labellums", but "labella" seemed pretentious, and liable to confuse.