‘It lives underground and is fabulous’: The race to save the world’s rarest orchid

The world’s most mysterious and elusive orchid lives underground in Australia. Scientists are trying to rescue this botanic marvel from going completely extinct.

As a child, Kingsley Dixon’s favourite book was Orchids of the West, about the wild orchids of Western Australia, where he lived. There was one illustration in particular that left him transfixed: an ink drawing of Rhizanthella gardneri, commonly known as the Western Australian underground orchid.

“From when I was tiny, I used to just look at this page and go: ‘oh my, there’s an orchid, it lives underground, it doesn’t have leaves, it doesn’t have roots, and it has this fabulous flower!'” Dixon recalls.

A self-described “little plant geek”, he spent much of his time in the Australian bush – the wild scrubland near his home in Perth – collecting orchids and then growing them on at home. “By the age of 13, I had a large collection of bush orchids, but the one sitting in the middle of the book, the Western Australian underground orchid – that was the dream, the dream of my life,” he says. The closest he got as a child was seeing a preserved specimen in a jar, during a special trip to a herbarium for his birthday. It would take him years to finally spot one in the wild, during a field trip to the small town of Babakin in Western Australia in 1982, when he was 24. “We stopped for a cup of tea […] and I wandered into the bushland and kicked some soil only to reveal some coloured bracts [of the orchid],” he recalls. “It was an absolute Eureka moment.”

Today, Rhizanthella gardneri is the one of the world’s rarest orchids and critically endangered due to habitat loss, with only a tiny number of plants surviving in the wild. The number fluctuates from year to year and in recent years has been as low as three or even none found at all, Dixon says, with climate change adding further pressure on the species. “It went in my own lifetime from [seeing] it, to watching this species slip away,” he says. So Dixon, now a professor of botany at the University of Western Australia and the former director of Kings Park and Botanic Garden in Western Australia, has a new dream: to save the underground orchid from extinction.

A special bond

Rhizanthella gardneri is not only the world’s rarest orchid, it is also one of the most mysterious. It’s the only known plant that flowers underground. It also grows, germinates and sets seed totally underground, and is thought to be pollinated by termites.

The orchid is able to survive underground thanks to an intricate and complex three-way alliance: it connects to an above-ground plant, the Melaleuca uncinata bush, through a white, thread-like fungus. The connecting fungus transfers nutrients from the bush to the orchid.

This kind of beneficial bond with fungi, known as a mycorrhizal association, is in fact typical of orchids in general, says Jacopo Calevo, a plant ecologist and orchidologist who has researched orchids and climate change in Europe and Western Australia. To understand how climate change affects orchids, one has to therefore look at the whole picture, he explains – the orchid, its special fungus, and in the case of the underground orchid, the Melaleuca uncinata bush as well.

“It’s estimated that about 80-90% of land plants have a mycorrhizal association. But the extent to which orchids are associated with fungi, is unique,” says Calevo, an honorary research associate at the Royal Botanic Gardens, Kew, in London, and an adjunct research associate at Curtin University in Australia.

Orchid seeds are typically very small, and don’t contain enough nutrients to help the seed germinate, Calevo explains. “So to germinate, [the orchid] has to associate with a fungus that usually lives in the soil, that transfers the nutrients to the embryo,” he says. As a result, “fungi are pivotal for the germination of orchids, so without fungi, the orchids cannot exist” in the long term, he says.

For the underground orchid, this complex life-support system is even more intricate.

“Other orchid species usually have one interaction – one orchid with one fungus or multiple fungi,” Calevo says. But the underground needs both the fungus, and the bush. “So this makes the underground orchid more vulnerable to a stressful event in the environment,” he says. “If anything happens to the bush, the fungus cannot transfer nutrients to the orchid anymore, and the orchid can’t survive in the long term.”

Heat and fires 

Calevo has examined the impact of climate change on orchids in Western Australia as part of a wider orchid conservation research project hosted by the Royal Botanic Gardens, Kew, London, and the Curtin University of Western Australia. Modelling the impact of a potential temperature rise of up to 5C (9F) over the space of a century, from 1970-2070, on 26 different Western Australian orchids, Calevo found that they were likely to survive, thanks to having evolved to cope with Australia’s extreme heat (the resulting paper has not yet been published). For example, spider orchids can lower their tubers to cooler depths in the soil.

But temperature rises are not the only aspect of climate change, Calevo points out. He warns that other climate-related phenomena, such as more frequent wildfires, could spell more trouble for Australia’s orchids. A 2025 study on the impact of fires on 17 Western Australian orchid species other than Rhizanthella found that there were more losers than winners in terms of the impact, with two-thirds of the species negatively affected by fire, and only one-third benefiting from it.

One of the winners in the study is Pyrorchis nigricans, known as the fire orchid, which needs fire to flower; while one of the losers is the blue sun orchid, Thelymitra macrophylla, which was almost completely wiped out in fire areas in Western Australia, according to the study.

Calevo and his colleagues studied the impact of a 2022 fire on Rhizanthella orchids and their associated fungi and Melaleuca bushes. While the findings have not yet been published, samples taken from the area showed that one year after the fire, the fungal community in the burnt area was completely different to fungal communities in the two other, pristine areas, he says. It was dominated by fungi that are known to colonise a recently burnt or cleared area, and the orchid would not have been able to grow in that changed fungal community, he explains. Also, the Melaleuca bushes were completely burnt.

However, two years after the fire, the fungal community had recovered to the point where it was comparable to that in the pristine habitats, Calevo says: “It shows the resilience of the fungal community in the soil.” And the bushes were resprouting. Fire may in fact boost the health of Melaleuca bushes in the long run, research suggests.

The Rhizanthella orchid can lay dormant for several years, Calevo says. So far, no Rhizanthella orchids have been found in the fire-affected reserve. But given that the fungus and the Melaleuca bushes are recovering, “it is likely that the underground orchid will come back”, he says.

However, Calevo warns that this kind of recovery won’t work if wildfires become so frequent that the beneficial fungi and bushes can’t regrow in time for the orchid to come out of its dormant state.

So-called prescribed or controlled burns, used intentionally in Australia to clear areas and make them less susceptible to wildfires, can also harm orchids, for example if the fires burn when the plants should be flowering, Calevo says. The orchids may then stay dormant instead, to protect themselves against the heat, one study suggests. Another West Australian study also reports that managed fires can affect orchids, in one case, apparently causing a further decline in the already-endangered Queen of Sheba orchid.

Both Dixon and Calevo emphasise that habitat destruction is making it even harder for the underground orchid to deal with climate change. Around the world, many plants are responding to hotter temperatures by expanding their range into cooler areas. But that’s only possible if enough suitable habitat remains to escape to, they explain.

“That’s the calamity facing threatened species around the world, the loss of habitat, and then, nowhere to escape to,” Dixon says. “There’s nowhere to go, because it’s [been turned into] a suburb, it’s a highway, it’s a farm – it’s cleared, it’s gone.”

In his view, this makes it all the more important to shield the remaining habitats, and raise awareness of the vanishing orchid. At the Chelsea Flower Show in London in May 2025, Dixon, Calevo and other orchid specialists from around the world put on a special display of orchids, including a picture of the underground plant, to highlight the urgent need to protect them. And Dixon is working on another, parallel plan to save the species: he is trying to grow underground orchids, complete with their fungi and Melaleuca bush, in a lab.

Captive orchids

Dixon and his team already managed to grow a living, captive collection of Rhizanthella orchids with their fungi and bushes once, in the 1990s. That collection died around 2000 due human error, in the form of an unclear watering rota that left the plants dried out after one Christmas holiday, he says.

While frustrating, this did not seem as catastrophic at the time, Dixon says, given that back then, there was still a relatively healthy number of underground orchids left in the wild, around 180. But then, about four years ago, teams surveying the orchid in those reserves started coming back with alarming results: the wild population “seems to have collapsed”, Dixon says.

A captive collection would provide an important back-up, should the orchid really go extinct in the wild. So far, Dixon says, the process is looking promising. It involves the same process that was successfully used in the 1990s: growing Melaleuca bushes in pots, reviving stored fungi in the lab, and then putting the fungi and orchid seeds on the Melaleuca’s roots. Dixon says he has already successfully revived the fungi in a lab at the Orchid Research Facility at the University of Western Australia in Perth. The bushes, in pots, are also growing well, he says. The last step will be to use a little bit of precious, stored Rhizanthella seed – and then, hope that it germinates, and grows. While the quest to study and protect the orchid’s habitat involves a range of researchers and volunteers, when it comes to trying to grow the orchid in the lab, Dixon says it’s currently just him and “a band of hearty community volunteers”.

For Dixon, there is no question that the slow, painstaking process is worth it, as he carefully pieces together the fungus, the bush and the seeds. He does it, he says, “out of my great love, from when I was little, for the orchid”.