Secrets from the forest floor 1

by Alison Potter

Karen Wilson, Senior Research Scientist in the Plant Diversity division at the Royal Botanic Gardens Sydney. Photo: Jaime Plaza

Far below the rainforest canopy and hidden in the damp leaf litter, two highly unusual little species of flowering plants have been found for the first time near Blackheath, Bundanoon and Comboyne.

The two rare species share a trait that sets them apart from most other plants on the planet: they do not require sunlight for their survival.

While most plants have chlorophyll to make their own food through photosynthesis with the sun, the orchid Danhatchia australis and Thismia rodwayi (commonly known as Fairy Lantern) do not.

Instead, they rely on fungi living among their root filaments to break down the nutrients in the leaf litter and the soil for all their nourishment.

The first discovery was made by a keen naturalist from Wingham who didn’t recognise the odd plant he found, so he sent photos to Karen Wilson, Senior Research Scientist in the Plant Diversity division at the Royal Botanic Gardens Sydney, for identification.

The plants found in the two localities in the Sydney region were similarly brought to Mrs Wilson’s attention by the botanists who found them.

At a press conference held at UTS recently, she was asked why we haven’t seen these plants before. “These are the kinds of plants that people don’t see easily. You could stumble over them without even noticing because they are so tiny, growing in leaf litter in rainforest areas.”

Both species have extensive root systems and can survive for years unseen in the soil until favourable conditions arise. They only flower for a week or two, between late October and early January, she said.

Mrs Wilson is excited by these discoveries: the orchid is a new record for Australia, while the Fairy Lantern hasn’t been collected in NSW for over a century. Finding the orchid in two widely separated localities indicates that it is almost certainly native here and not an accidental introduction from New Zealand.

She explained that there is a mutualistic relationship between orchids and fungi whereby the fungi have something to live on and the plant gets fed the nutrients that the fungi have broken down. Much is still unknown about how this works.

The Fairy Lantern Thismia rodwayi doesn’t have proper leaves, just tiny white scales on a short white stem about one centimetre long, with its pinkish orange flower poking through litter on the forest floor, sitting up like Chinese lanterns.

Its recent discovery near Blackheath and Bundanoon is the first time it’s been found in NSW in over 100 years. Thismias are known to grow in Gippsland in Victoria, in Tasmania and New Zealand.

The orchid Danhatchia australis was thought to exist only in New Zealand until its significant discovery two years ago in remnant rainforest near Comboyne, and then also last year near Bundanoon in temperate rainforest. It is a stick-like orchid, growing to 15 centimetres, with small, pinkish brown-coloured scale leaves that hug the stem and small, similarly coloured flowers.

Mrs Wilson says there’s always a big debate amongst biologists as to whether to publicise where rare species are growing.

“People could go and destroy them by digging them up. But equally, if people don’t know they are there they could accidentally destroy them by treading on them. And if you don’t draw attention to these finds people don’t know to go looking for them in other areas.”

These finds, she said, show there is still much to learn about our environment. “Plenty of people have been walking in these areas without noticing these plants – in some cases they grow right by the track. I urge people to get to know the plants of their local area so they can spot any strange species like these.”

Amateur botanists who find unusual plants in the field may send them to the National Herbarium of NSW at the Royal Botanic Gardens Sydney for identification.

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One comment

  1. For detailed information about these mycoheterotrophic plants, how they function, and their relationships with fungi, see the various papers by Vincent Merckx.
    There is a new species of Fairy lantern from Blackheath, discovered and described by the same people that brought Thismia rodwayi to the attention of Karen Wilson. It has been called Thismia megalongensis.

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