Acianthella Orchids at Seven Mile Beach National Park

These plants have been known of for at least a year, when they were first reported by Matthew, in charge of a Landcare Group. 

He spoke with Alan Stephenson last year, who inspected the a few of these unusual plants, and concluded that they are a species of Acianthella. Little more is known about these plants, as they have not yet been found in flower.

Today I went with Alan and Matthew to again look for these plants, and we found quite a lot of them - approximately 50 plants in all.

The plants we found today were scattered around on the moist leaf litter of coastal mixed Eucalypt, Banksia and Casuarina forest and rainforest understory species, growing on sand dunes, behind Seven Mile Beach.  

Even for three quite experienced orchid people, they were hard to find.

This was the first of these Acianthella plants I saw today.
The leaf is held well off the ground
above the leaf litter
Growing over moist sand.
The lead surrounds the flower stem,
but it is classed as "sheathing" the stem.

CLICK ON IMAGE TO ENLARGE IT.
"Sheathing" is illustrated in Figure g
Source PlantNET Glossary

These plants hold the leaf off the ground, just above the leaf litter. 

A non-flowering plant
showing the lobed leaf shape.

A very young, non-flowering plant.
The leaf has not developed the distinctive lobed margins
but it clearly shows the notch
where the leaf is attached to the leaf stem.

Some of these plants had already flowered, but obviously their flower stems are very small, compared to their nearest relatives, the Acianthus genus. We saw lots of leaves of Corybas and Acianthus and many, many colonies of Pterostylis, but the Acianthella are much smaller in leaf and flower than any of those common Orchids. 

Seed capsules clearly visible
CLICK TO ENLARGE IMAGE.
There are two separate Acianthella plants growing closely together.

The leaves are very distinctive in texture and shape.
They are more or less club shaped (as in the cards of that name).

Juvenile plants sometimes have lobed leaf margins.
In more mature plants the lobes of the leaves can be quite pointed.

Leaf is 2 cm long,
with noticeable points to the leaves.

Leaf is approx 13mm wide.
There are two Acianthella plants growing side by side
Both have set seed.

As yet, we do not have any diagnostic details to identify the species of these plants.
 
The books report that the Acianthella genus is restricted to two species in Australia, and five species in New Caledonia. The Australian ones are one from north Queensland and Acianthella amplexicaulis is reported to extend only as far south as the littoral rainforest, north from Wyrrabalong National Park (just north from The Entrance, NSW).

So, if and when these plants are identified, then it will at the very least be an extension of the range, if the species is confirmed as Acianthella amplexicaulis.
 
However, it is also possible that these plants might be identified, in due course, as a new species in the genus Acianthella. As no flowering plants have yet been found, and recorded, it cannot be identified beyond the genus level at present.

That's a further challenge for next year.