Greetings fellow Foxies,
 
I was excited to find a Bird Orchid at a Dryandra Woodland reserve on Chomley Road, south-east of Highbury, because I hadn’t seen one for 60 years. My interest in wildflowers began then when my mother and I used to look for orchids in remnant bush at Karrakatta Cemetery. Alas now all graves.
 
This orchid has always fired my imagination with its elegant shape, translucence and the strange wispy labellum that gives the species name. Barbata means beard.
 
A few swipes of the trusty scalpel showed that bird orchids are basically redesigned greenhoods with a wispy labellum.
In this case the hood is folded inwards to form the entry and exit spots for gnats with essentially the same column tube and anther location.
 
I can’t work out how the wisps on the labellum prevent the gnat from escaping out the entry point, but it is hinged like other species to close when activated.
I wonder if the wisps help to spread a pheromone to attract male wasps?
 
Unlike the Jug and Shell orchids there is no little structure at the base of the labellum to trap gnats and retain them for a miserable death

 Greetings fellow Foxies,
 
After dissecting greenhood orchids to see how they trapped insects I moved on to shell and jug orchids that have a more open appearance. In the shell orchid image below one can see that the lower two sepals are upswept rather than being down to form a landing platform, the hood is more open, and the labellum is much skinnier. A few deft slices of my trusty scalpel revealed how this unlikely combination could force an insect to pollinate the flowers. Near the base of the interior the hood petals fold in and the labellum widens to seal the chamber containing the column tube.
In the cross-section below the labellum is closed, but if you picture it leaning forward, imagine a male gnat crawling down it, following the plant-made scent of a female (pheromone).
When the gnat get to the base, the labellum snaps forward, forcing it to climb the column (leaving behind pollen attached its body), through the tube where it gets another dose of pollen, and out of the flower.
Can you see a gnat that was trapped by a curly bit at the base of the labellum? It is the remains of a Fungus Gnat (rather appropriate that it has been consumed by a fungus), whose maggots consume mushrooms, but more of this below.

The Jug Orchid, Pterostylis recurva has an even more open- looking structure than shell orchids, but it is just a modification of the shell orchid layout.
It has the same infolded petals and thin labellum with widened base and little horns at the top of the column tube to position the labellum when closed.

The Frog Greenhood Orchid has looks like it has has a club-like labellum, but the club part is actually a counter weight that snaps the labellum closed when the gnat enters