All 42 known species of the parasitic plant genus Rafflesia, often known as ‘corpse flowers’, are endangered due to runaway destruction of their tropical forest habitats.
Some of the world’s most enigmatic plants are the mysterious Rafflesia species that occur throughout southeast Asia. As plants go, Rafflesia species are wildly weird. They live hidden inside a vine most of the time, lack any observable leaves, stems or roots – they even lack chlorophyll, thus, they cannot do as most plants do: they cannot photosynthesize. Of course, this made me wonder how do we know Rafflesia actually are planets and not fungi?
“[L]ots of plants lack chlorophyll (and even leaves); but besides a vascular system, Rafflesia has all the floral parts you’d expect a flowering plant to have (stamens, pollen, stigma etc.) – and it produces a fruit with seeds,” explained botanist Chris Thorogood in email. Dr Thorogood is the Deputy Director & Head of Science at University of Oxford’s Botanic Garden & Arboretum where he studies speciation and adaptive radiations in cryptic parasitic and carnivorous plant groups, particularly Rafflesia species. He also is a writer and botanical artist.
“Really, it’s nothing at all like a fungus, physiologically, anatomically or genetically – it just happens to grow inside another plant in a similar way (= convergent evolution),” Dr Thorogood continued.
Basically, Rafflesia are accomplished thieves, a botanical tapeworm that lives hidden within a vine that they parasitize; making their living by stealing nutrients and water – and also mitochondria – from their host plants. Remarkably, they even steal DNA from their plant hosts in a process known as horizontal transfer, which is common in bacteria. Their molecular kleptomania makes Rafflesia unique amongst vascular plants. It also makes it quite difficult to study their genetics and phylogeny.
If all these peculiar traits are not enough to pique your interest, you may be interested to learn that Rafflesia species produce a large cabbage-like bud that turns into a giant rubbery flower – some are spectacularly large, as big as 122 cm (4 feet) in diameter – hence one of their common names, the “monster flower”. And these flowers look and smell like rotting flesh, thereby giving them another common name, the “stinking corpse lily.” Their revolting stench attracts flies and other insects that are irresistibly drawn to the smell of carrion. These insects end up being coated with a thick, sticky liquid that dries onto their bodies and serves to pollinate the flower.
Why are the flowers so big if the plants are relying on flies (not so big) to pollinate them?
“Great question,” Dr Thorogood replied in email. “Fly-pollinated flowers have sprung up across the flowering plant family tree. They resemble corpses (reddish-brown coloration, hairiness and so on), and crucially, they smell really bad – this dupes flies into thinking a flower is a resource for them to lay eggs on.”
“Rafflesia flowers are no exception: they ‘pretend’ to be corpses to attract flies through fraud – enticing them with the stench of rotting meat to pick up and deliver pollen, with no reward,” Dr Thorogood explained in email. “In other words, Rafflesia is a stinking great sham! Female flies are targeted specifically, because their maternal instincts are exploited: the bigger the corpse, the better the resource for their offspring. Similar white lies have sprung up all over the plant kingdom in this way; but Rafflesia wins the prize for the biggest.”
Despite its enigmatic nature, Rafflesia species have long been used for medicinal purposes by Indigenous Peoples and, more recently, as a source of revenue generated by ecotourism. And yet, despite their popularity and the intense scientific curiosity that they’ve inspired, these plants are poorly understood because they are difficult (or even impossible) to cultivate, and its seeds cannot be stored for long periods.
Unfortunately, at this time, only one species of Rafflesia (Rafflesia magnifica) is officially listed as “Severely Endangered” by the biodiversity conservation organisation, the International Union for Conservation of Nature (IUCN). But Dr Thorogood and an international team of collaborators argue in their recently published review of the conservation status of the genus (ref) – the first such assessment of the threats facing these magnificent plants – that all 42 known species of Rafflesia (Figure 1) should be added to the IUCN ‘Red List’ of threatened species.
According to estimates by Dr Thorogood and collaborators, 60% of all known Rafflesia species face a severe risk of extinction (Critically Endangered [CR]) due to wholesale habitat destruction and deforestation for timber extraction and conversion to oil palm plantations and other monoculture crops. Dr Thorogood and collaborators report that many populations are estimated to number just a few hundred individuals. Further, they note that at least 67% of known Rafflesia habitats are not protected at all, thereby intensifying these plants’ overall vulnerability.
“Alarmingly, recent observations suggest taxa are still being eradicated before they are even known to science,” Dr Thorogood and collaborators warn in their review (ref).
What can we do to help protect and conserve these incredible plants?
“We propose a multi-pronged conservation approach combining strengthened taxonomy, ex situ propagation, ecotourism, and an extension of protected areas,” Dr Thorogood and collaborators write. This conservation approach should also include campaigns to raise public awareness on social media networks designed to protect areas where these plants live. Further, Dr Thorogood and collaborators are encouraging ecotourism so local Indigenous communities can benefit from Rafflesia conservation.
“Indigenous peoples are some of the best guardians of our forests, and Rafflesia conservation programs are far more likely to be successful if they engage with the local communities.”
“Finally, we propose to establish Rafflesia as a new icon for plant conservation in the Asian tropics,” Dr Thorogood and collaborators write hopefully (ref). “A combined approach might just save some of the world’s most remarkable flowers, most of which are now on the brink of being lost.”
Source:
Pastor Malabrigo Jr., Adriane B. Tobias, Joko Witono, Sofi Mursidawati, Agus Susatya, Mat Yunoh Siti-Munirah, Adhityo Wicaksono, Reza Raihandhany, Sarah Edwards, and Chris J. Thorogood (2025). Review: Most of the world’s largest flowers (genus Rafflesia) are now on the brink of extinction, Plants, People, Planet 7(2):331–346 | doi:10.1002/ppp3.10431
More reading:
You may wish to read Dr Thorogood’s most recent book, The Pathless Forest: The Quest to Save the World’s Largest Flowers (Penguin Books, 2025; Amazon US / Amazon UK), which tells the story of his journey to find and document these magnificent plants in the wild. (My review is coming soon.)
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