Kew’s 2021 top ten new species list

A reminder of the need to find and name unknown species to protect them before they become extinct

Release date: 6 January 2022

  • RBG Kew selects 10 highlights from 205 plants and fungi named new to science in 2021, plus the first plant named in 2022
  • A killer tobacco plant found in Australia, a pink voodoo lily from the threatened Ebo Forest in Cameroon and a ‘ghost’ orchid among the showstoppers on Kew’s list
  • Several of these new species are already extinct, and many threatened, due to deforestation, land-use change and climate change

Scientists from the Royal Botanic Gardens, Kew and their collaborators around the world have selected their top 10 highlights from the list of plant and fungal species named new to science in 2021, plus the first plant species named in 2022, Uvariopsis dicaprio, published today in leading journal PeerJ.

From a ghost orchid that grows in almost complete darkness, to a tropical pink voodoo lily found in Cameroon’s threatened Ebo rainforest, to an insect-trapping tobacco plant; 2021’s top picks represent the amazing breadth of plant and fungal species named new to science every year and highlight the incredible diversity of species out there still to be documented.

For more than 150 years, scientists at RBG Kew have been hard at work studying unknown species around the globe, finding their places in the tree of life, assembling the data needed to provide evidence that they are new to science, deciding on what name should be used and publishing them in scientific literature.

In 2021, RBG Kew and their partners named approximately 205 plants and fungi from Africa, Asia, the Americas and even here in the UK. Some of these new species could be important for people and planet – providing vital income to communities, having the potential to be developed into a future food or medicine, or simply keeping the habitat around them thriving.

Dr Martin Cheek, Senior Researcher in RBG Kew’s Africa team says: “It’s easy to assume that we know all of the plant and fungi species on our planet. There are wonderful apps that enable identification of plant species in the UK and other countries where species diversity is low and well-studied. But in most parts of the tropics, identification of plants is still a big challenge, and thousands of species still remain without scientific names. This is a problem because until a species has a scientific name, assessment of its extinction risk is near impossible, and that makes protection from extinction and research into its properties, incredibly difficult.

“Sadly, several species in 2021’s list are already considered as under threat of extinction from increasing threats to their natural habitat, and three are already believed to be extinct in the wild. This list is another reminder that this is our last chance to find unknown species, name them and hopefully protect them before they become globally extinct.”

Here Kew scientists select their top ten weird and wonderful species from 2021:

1. A killer insect-trapping tobacco plant collected in Western Australia…

Scientists from RBG Kew, Curtin University and the University of Vienna, named seven new species of Nicotiana (wild tobacco) from Australia in 2021.

One of the seven species described by scientists was Nicotiana insecticida, which has sticky glands covering all its surfaces and regularly snares and kills small insects such as gnats, aphids and flies – the first time a wild tobacco species has been reported to kill insects.

Its seeds were collected by a truck stop on the Northwest Coastal Highway in Western Australia and cultivated back in London in the glasshouses at Kew Gardens, where the plants continued to kill insects. So, its insidious deadly nature is not diminished by the great distance from its homeland.

Professor Mark Chase, scientist at RBG Kew says: “The arid parts of Australia, which include most of the continent, have been thought of as almost barren with limited plant diversity, but in recent years these poorly studied areas have yielded many new and unusual species. One of these, Nicotiana insecticida, demonstrates well the adage that ‘tobacco kills’, although in this case it is insects that become ensnared on its sundew-like glandular hairs and die.”

2. A new species of fungi hidden within a wild banana seed at Kew’s Millennium Seed Bank…

One of the most unexpected species in the 2021 list is a microscopic new fungus, Fusarium chuoi, found growing in a wild banana plant seed in Kew’s vast collection at the Millennium Seed Bank, in Wakehurst, Sussex. The new species was described by a group of scientists from the Westerdijk Institute in the Netherlands, the Plant Resources Centre in Vietnam and RBG Kew.

Although the Millennium Seed Bank acts as a safehouse for plant seeds, this is the first time a new species of fungi has been described from its collections. Kew scientists found it by placing seeds on agar under sterile conditions, which allowed the fungus inside to grow out and be isolated in the lab. When grown on agar, F. chuoi has a coral colour and a velvety texture.

Named for the Vietnamese word for banana, ‘chuoi’, reflecting the country and plant host where it was found, F. chuoi is what is known as an endophyte – a microscopic fungus that lives inside a plant without causing it any visible harm. Finding new endophyte species and understanding if and how we can tell them apart from pathogens is crucial for protecting plant health.

3. 16 new orchids including a ‘ghost’ orchid that grows in almost complete darkness…

An incredible 16 new species of orchids, all from the biodiverse island of Madagascar, were named by Kew scientists Johan Hermans and Phill Cribb this year, in collaboration with Landy Rajaovelona and Malagasy researchers at the Kew Madagascar Conservation Centre in Antananarivo. Many of the orchids were found in remote, previously unexplored sites and have tiny geographical ranges.

One of these is a fascinating ‘ghost’ orchid, Didymoplexis stella-silvae, named by Hermans as the ‘star of the forest’ as it grows in almost complete darkness and has star-like flowers. The orchid is leafless and depends entirely on fungi for its energy. It’s unique bright white flowers only open immediately after rain before disappearing 24 hours later.

Unfortunately, three of these 16 new species were already thought to be extinct in the wild before they were officially published in scientific papers, due to destruction of their habitat. This includes a tree-dwelling orchid, Aerangis bovicornu, likely eradicated due to clearance of its forest habitat for the cultivation and production of geranium oil, which is in high demand in Europe for aromatherapy; Habenaria crocodilium, first found by a crocodile enclosure that is now thought to be lost to a climate change driven flash flood; and a third, likely extinct in the wild, Bulbophyllum cochinealloides, which survives only as one plant in cultivation in Europe.

Johan Hermans, Honorary Research Associate at RBG Kew says “Sadly, Madagascar’s many unique plants are under threat from deforestation, land-use change and droughts, floods, and fires caused by climate change. It really is a race against time to document the island’s incredible biodiversity before it’s lost.”

4. A beautiful blue Barleria uncovered on a National Geographic expedition in Angola…

This beautiful blue BarleriaB. thunbergiiflora – was named new to science in 2021 after being collected by Kew scientist David Goyder on a National Geographic expedition to Angola. 

National Geographic supports scientific expeditions to remote, biologically unknown areas of the world to uncover spectacular new species such as this pretty tropical flower.

Iain Darbyshire and colleagues from Namibia and USA named the plant after the showy genus of flowering plant Thunbergia, after noticing a likeness in their flowers. The Barleria only grows in three sites in high elevation grassland on Kalahari sands, a large sand sea that extends from the northern Cape Province, South Africa, towards the equator. The species was one of six new species of Barleria published last year from Angola and Namibia.

5. A pretty Cape primrose at risk of extinction due to copper mining…

Five new species of Cape primroses (in the genus Streptocarpus) were named new to science in 2021 from the Democratic Republic of Congo.

Streptocarpus plants are commonly cultivated around the world as houseplants, but in the wild many are highly localised, making them vulnerable to extinction, especially if they grow on areas of land in demand by humans for development.

This is the case for one of the five new species, Streptocarpus malachiticola, from Katanga in Congo. The Latin meaning of its name means ‘growing on malachite’ – malachite is an ore of copper, and it is regularly extracted from mines found in this area of the country, the main mining province for Congo.

With global copper prices at an all-time high due to demand for electrical wiring (electric vehicles require up to 80kg of copper to build), this sadly means the species, restricted to just three locations, is assessed as Endangered under the Red List criteria of the International Union for Conservation of Nature (IUCN).

6. Exploding firework flower threatened by palm oil plantations…

Named for its resemblance in flower to an exploding firework, this new species, Ardisia pyrotechnica, was named by a group of Malaysian and Japanese scientists in collaboration with Dr Tim Utteridge from RBG Kew.

The spectacular plant, a member of the primrose family, was found in the forest in Borneo and grows up to four metres tall.

One of the scientists who helped to name the species, Shuichiro Tagane from Kagoshima University, says: “The firework forest primrose is named for the white flowers that stand out brilliantly when the plant flowers in July, and seeing the magnificent, flamboyant flowers is a real sparkling pick-me-up in the hot and humid tropical rainforest.”

Unfortunately A. pyrotechnica is already assessed as Critically Endangered under IUCN criteria, as it has only been found growing in two locations with a handful of plants and is under threat from plantations of palm oil. Around 700 species of Ardisia are known throughout tropical and subtropical rainforests, many rare and threatened with extinction, and new finds are made most years.

7. A rare British fungus with teeth instead of gills…

A rare tooth fungus from the UK, Hydnellum nemorosum, enters the 2021 list despite being collected from the Crown Estate in Windsor Great Park in 2008.

Found growing in moss under a sweet chestnut tree over 13 years ago, researchers then collected samples that mycologists used to describe the species as new to science in 2021.

A DNA-based analysis of European specimens carried out at RBG Kew with collaborators in Wales and Sweden revealed that Windsor is its only known site in Britain — so it has already been proposed for inclusion on the IUCN global Red List of threatened species and for legal protection under the Wildlife and Countryside Act in Britain.

The new species is one of group of rare fungi that form mushrooms with teeth under their caps, in place of gills. They thrive in poor soils with low nitrogen levels and have a mutually beneficial partnership with living tree roots, swapping soil minerals for leaf sugars. Their populations have declined across Europe due to habitat loss and elevated levels of nitrogen in the air. Today they are recognised as threatened with extinction at global and national levels and are prioritised for conservation and protection.

8. A Bolivian periwinkle with edible fruits and potential medicinal value…

This vivid and unusual periwinkle, Philibertia woodii, from the Andean valleys in Bolivia, was collected in the wild and named new to science by Argentinian botanist Hector Keller and RBG Kew scientist Dr David Goyder.

The new bright, yellow-flowered plant has egg-shaped kiwi-like fruits that are edible when roasted, and its vivid and attractive flowers are popular with butterflies. Many species in the periwinkle family are medicinal so it is hoped the compounds of this species will be analysed for their potential.

Keller and Goyder named the new species for John Wood, a botanist, to honour his dedication to training Bolivian botanists and supporting botanical expeditions in Bolivia for many decades.

9. A weird and wonderful pink voodoo lily…

This extremely rare species, Pseudohydrosme ebo, is restricted to a small corner of the vast and amazingly diverse Ebo Forest of Cameroon, home to the Banen people, threatened gorillas, chimpanzees, forest elephants and 75 threatened species of plant, of which eight are unique to the forest.

The voodoo lily flowers from an underground tuber when its leaves have died back, and the flower spike can reach 30 cm in height. It is the only member of the genus in Cameroon, with all the other species found in neighbouring Gabon.

It was named by Kew botanist Dr Martin Cheek.

10. A Borneo blue-berried bush painted by Marianne North in 1876, and named in 2021…

Fourteen species new to science of bright-blue-fruited rainforest shrubs in the coffee family, Rubiaceae, were recognised, named and published in 2021 by scientists from RBG Kew and Queen Mary University of London.

Incredibly, one of these is thought to be the first of the Bornean Chassalia species ever to be illustrated – in an oil painting from 1876 by the eminent Victorian artist Marianne North.

At the time of the painting, Marianne was staying in Kuching on the Sarawak River with the Rajah and Ranee of Sarawak. Today the painting is preserved as one of more than 800 by North in the Marianne North Gallery in Kew Gardens. So far as we know, the first herbarium specimen (which is needed to characterise the species) of this plant was not collected until 1973, nearly 100 years later.

Lead researcher on the study, Tianyi Yu who was previously a student at Kew, named the species Chassalia northiana in Marianne’s honour, only the fifth plant species to bear her name.

Twelve of the 14 new species have small geographic ranges in Borneo, meaning they are potentially threatened by habitat clearance, but fortunately several of these areas are already protected as national parks. In contrast, the other two species are widespread across Borneo and so are unlikely to be threatened.

And new for 2022

11. The Uvariopsis dicaprio tree in Ebo Forest, Cameroon.

A tropical tree from Ebo Forest in Cameroon is the first addition to Kew’s 2022 new species list and is published today in leading journal PeerJ. A member of the ylang-ylang family, the new species, Uvariopsis dicaprio, was named after actor and environmentalist Leonardo DiCaprio by a group of international scientists from RBG Kew and the National Herbarium of Cameroon. The tree, collected by Kew scientist Lorna MacKinnon, is four metres tall with bunches of large, glossy, bright yellow-green flowers on the trunk.

The scientists chose to name the new tree in honour of DiCaprio after he took to social media, in an effort alongside Re:wild, to revoke a logging concession for the precious Ebo Forest in February 2020. Ebo Forest makes up one half of the Yabassi Key Biodiversity Area, home to the world’s only known chimps to both crack nuts and fish for termites, and the ancestral home of several local communities. The cancellation of the concession in August 2020 by the President of Cameroon gave hope that the many unique and threatened species in the forest would escape the extinction they would have otherwise faced.

Dr Martin Cheek says, “We very much appreciated the support Leo gave us in campaigning to protect Ebo last year so it seemed fitting to honour him in this way, naming a species unique only to this forest, after him. Had the logging concession gone ahead, we would have likely lost this species to timber extraction and slash and burn agriculture that usually follows logging concessions.”

Ebo Forest is one of the largest intact rainforests in Cameroon, home to incredible wildlife, but has previously been relatively unknown to botanical science. Scientists at Kew with their partners at the National Herbarium of Cameroon have been documenting the incredible array of plant species in Ebo Forest and collecting data, supporting the San Diego Zoo Wildlife Alliance who have been leading efforts with local communities to protect the forest for almost twenty years.

Sadly, U. dicaprio is already assessed in the paper as Critically Endangered, because the forest habitat it occurs in remains unprotected meaning threats of logging and conversion of the habitat to plantations remain, and mining is an additional threat.

This newly named tree species is part of Kew’s Cameroon TIPAs (Tropical Important Plant Areas) project with the National Herbarium of Cameroon, supported by Players of People’s Postcode Lottery.

N.B. In botany, plants are often named in honour of people, often after other scientists who have shown a commitment to the research field or area.



About the Royal Botanic Gardens, Kew

The Royal Botanic Gardens, Kew is a world-famous scientific organisation, internationally respected for its outstanding collections as well as its scientific expertise in plant and fungal diversity, conservation and sustainable development in the UK and around the world. Kew Gardens is a major international and a top London visitor attraction. Kew Gardens’ 132 hectares of landscaped gardens, and Wakehurst, Kew’s Wild Botanic Garden, attract over 2.5 million visits every year. Kew Gardens was made a UNESCO World Heritage Site in July 2003 and celebrated its 260th anniversary in 2019. Wakehurst is home to Kew's Millennium Seed Bank, the largest wild plant seed bank in the world. The Kew Madagascar Conservation Centre is Kew’s third research centre and only overseas office. RBG Kew receives approximately one third of its funding from Government through the Department for the Environment, Food and Rural Affairs (Defra) and research councils. Further funding needed to support RBG Kew’s vital work comes from donors, membership and commercial activity including ticket sales.