Wasp Orchid - Chiloglottis reflexa - comes into flower

This group of "Short-clubbed Wasp Orchids" (Chiloglottis reflexa) is flowering right on the edge of one of the local roads in Kangaloon. Alan Stephenson spotted them when we were out admiring a large clump of Hyacinth Orchids, nearby. 

Look for the paired leaves on the ground. 
There are two open flowers and two buds visible.

They are small plants and even smaller flowers, 

as made evident by the scale of Alan's camera lens.

(Click to see the flowers)

Wasp Orchids - in situ - in leaf litter

 Here are two of these flowers together.

As plants which grow in colonies, it is quite common to get

two or more flowers together in a single image.

Chiloglottis reflexa - a pair of these tiny flowers

The "insectiform callus" (gland in the shape of an insect) covers most of the labellum of the flower. 

In other species the shape or position of the callus is different.

(Click to enlarge image)

Chiloglottis reflexa

These plants get their name "Wasp Orchids" from the "callus" - the glands on the labellum which resemble the body of a female wasp. They are part of a large group of Orchids which employ what is termed "sexual deception", to induce male wasps to attempt copulation with the flower, in order to achieve their own pollination (the Orchids that is). It used be referred to as "pseudo-copulation", but that term has gone out of favour in this more politically correct age. The technical people who have studied this phenomenon say it is both a visual trick and a scent based mimicry of the pheromones of female wasps.

The reflexed "Lateral Sepals" are clearly visible beneath the labellum.

A detailed look shows two points of note.

1. There is a pair of Aphids (adult and nymph) on the stem of the Orchid.
2. More unusually, the petal on the near side of the flower is showing some aberrant growth of calli (glands) which is normally restricted to the labellum only. The petal is reflexed down against the stem in its mature position (once the flower has opened). But in the development of the flower, the petal is adjacent to the labellum (which botanically is simply a modified petal). So the fact that some of the glandular development has crossed over to the lateral petal is not entirely surprising. But it is the first time I have seen this occur.

 Aberrant "callus" growth on the reflexed petal - that is unusual. Two Aphids.

This over-exposed photo (accidental I assure you) serves almost as an X-ray to highlight the shape of the head of the insectiform callus. Different members of this and related genera have different shaped "heads" or "necks" to these glands. So, although the image is weird, it is actually quite useful. In this case the head is clearly heart-shaped when seen from the front of the flower.

(Click to enlarge)

Accidental over-exposed image, but it shows well the shape of the "head" of the callus

That heart-shaped head of the insectiform callus is clearly visible in right hand image in the botanical illustration, from PlantNET.

Illustration from PlantNET - for Chiloglottis reflexa.

This is the first of the summer/autumn flowered Chiloglottis which I have seen this season. Something to look out for, obviously. They are most easily seen by looking for the mid-green, flat leaves, in opposite pairs (growing away from eachother) on the ground. Once you see one, there are usually more around, as they tend to grow in colonies. These plants were growing in loose grey sandy soil, over sandstone, within a Eucalypt forest.