A spectacular orchid sold from a barrow in a Laos market, a flower which may contain cancer-fighting chemicals, and a tall tree found beside an African highway, are among more than 100 plants that were newly discovered by science in 2018. But experts warn it is a “race against time” to discover many new species before they become extinct.

Species hunters scouring the globe for the Royal Botanic Gardens, Kew, and its partners, this year found about 128 vascular plants and 44 species of fungi.

The plants new to science include a species of allspice (used around the world in a variety of dishes), an insect-eating pitcher plant, a climbing species of yam, and an edible “hedgehog mushroom”.

Facebook Twitter Pinterest Dioscorea hurtii, a climbing yam, located in KwaZulu-Natal, South Africa. Photograph: Neil Crouch/RBG Kew

The largest organism newly listed by Kew this year is the Talbotiella cheekii, a rainforest tree which can grow up to 24 metres and which has fruit in exploding pods. Once thought to be common, it is endangered in Guinea, west Africa, because of clearance of the remaining fragments of rainforest on the coastal plain. Specimens bearing the lurid pink flowers – needed to fully identify the species – were found in 2017 beside the N1 highway just 28 miles from the centre of the capital, Conakry.

The Kew plant hunter Xander van der Burgt, who found the tree, named the species after its first collector, Martin Cheek, a Kew botanist, who used Google Earth to locate promising-looking remnants of rainforest before travelling there to hunt for overlooked species.

Cheek, a senior scientist within Kew’s “science identification and naming department”, said: “Finding a canopy rainforest tree that’s new and near an international highway and in an area of forest that’s all but gone is pretty unusual. But it was astounding because the Talbotiella is primarily a genus of Cameroon and Gabon. To find any Talbotiella species this far west was quite gobsmacking.”

Cheek said it was “unbelievable” that we are still discovering species of plants and fungi new to science but warned that an increasing number of new finds, including Talbotiella cheekii, are in unprotected areas and highly vulnerable to extinction.

He said: “When I began 30 years ago there was mostly nothing to suggest that new species I was publishing were about to go extinct. Increasingly I’m finding that species I’m describing are endangered or even extinct already.

“There is no doubt it is a race against time. Until species are officially discovered and given a name, the International Union for Conservation of Nature won’t accept a conservation assessment for them. Then the species has got a better chance of surviving.”

Cheek has published a paper detailing the discovery of a tree in Cameroon, called Vepris bali, which is thought to have become extinct before it had even been named. He hopes its naming will encourage people to search for it, after it was found some years ago in the Bali Ngemba forest reserve in Cameroon.

Facebook Twitter Pinterest Hydnum melitosarx (Cantharellales), a hedgehog mushroom, discovered this year by Kew mycologists Tuula Niskanen and Kare Liimatainen. Photograph: Kare Liimatainen/RBG Kew

“Many of these new species have potential benefits for humanity, from beautiful pot plants to new medicines or crops, but sadly we are finding that most of these new species are threatened with extinction due to habitat destruction, or are even likely extinct already.”

Another plant, Lebbiea grandiflora (of the Podostemaceae family), a new genus featuring unusual pillar-like structures, was found in a waterfall in the Sewa river rapids in Sierra Leone. It is already classified as critically endangered due to threats from mining and a hydro-electric dam project. Scientists fear it will be extinct within the next two years and Cheek is planning to collect seeds in 2019 for ex-situ conservation.

Facebook Twitter Pinterest The slipper orchid Paphiopedilum papili-laoticus found on the black market in Laos. Photograph: Adunyadeth Luang Aphay/RBG Kew

The slipper orchid, Paphiopedilum papilio-laoticus, was discovered on a black market in Vientiane, the capital of Laos, by Andre Schuiteman, another Kew scientist, who described the plant as an “outstanding but gravely endangered species of great horticultural potential”. That species is threatened because of commercial plant collectors illegally trading wild-collected native plants on local markets and over the internet.

The delicate white flowering plant Kindia gangan, was found growing high on sandstone cliffs near Kindia, Guinea. Its finders believe its bell-shaped white flowers are pollinated by bats. Bright orange pollen later analysed by Melanie-Jayne Howes, a scientist at Kew, was found to contain more than 40 different triterpenoid chemicals, known for their medicinal value and of particular interest for anti-cancer research.