Looking at Unusual Orchids – 27 September 2020

Back in August, I had been invited to see some rarely seen and very unusual orchids growing at a location in the Lane Cove Valley. Back then the orchids were only buds. I was recently invited back to see them in flower. The orchids are Rhizanthella slateri – an underground orchid.

This patch had been found by Vanessa McPherson and Michael Gillings, and it was a real privilege to be able to see them. They are certainly a most extraordinary plant. I believe that underground orchids are only found in Australia. They are perhaps quite common, but are rarely seen because their flowers develop underground. Vanessa and Michael found two clusters of them, close together,  in a gully in a tributary of the Lane Cove River. They were searching for club and coral fungi at the time – and were looking under the leaf litter when they found the developing buds. Between inspections of the developing flowers, they covered them with leaf litter. If they were not covered the flowers would not develop.

Here are some photos of them from the earlier trip showing the developing buds –

I think all of the buds in the one cluster may be flowers from the same plant.

It is interesting that one patch is paler than the other in colour.

These orchids have a very interesting ecology. Growing underground, the plants do not photosynthesise. Instead they get all their nutrients from a fungus, and the fungus in turn is in a symbiotic relationship with another plant – probably a tree. It is not known what pollinates the orchids. Perhaps ants. Later the seeds, which are relatively large for orchids are dispersed possibly by bandicoots, which may eat the fruiting bodies.

When you look at the flowers closer you can see they do have a the typical orchid structures. You can also see the yellow pollinia.

I would like to thank Michael and Vanessa for inviting me along to see these very special orchids.

We later looked around the bush nearby and found some more orchids –

Caladenia sp.

Flying Duck Orchids (Caleana major)

This last photo shows the buds of developing Bonnet Orchids (Cryptostylis erecta)

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4 Responses to Looking at Unusual Orchids – 27 September 2020

  1. John Joshua Terania says:

    Hello!
    I am a freshman student currently working on my general botany laboratory report. The report is currently focusing on the different kinds of plant specialized roots and one of plant specimens that needs to be studied is the Rhizanthella slateri. I was wondering if I could get a high resolution copy of just one picture shown on this blog. I’m still a student and do not have the money to buy images online, I am definitely taking my chances here but hopefully you can see this on a good note. Rest assured that I will be properly crediting you as the owner of photos on my laboratory report. I hope you find this comment well! Thank you!

    • Dave Noble says:

      Yes – that is OK. Did you want any particular photo? Or want me to choose one. Give me a day or two to locate the originals.

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