There are more than 140 species of palm in the genus Pinanga, most of which are small, erect palms that can be found along the forest understory. More than 100 of these species occur in Southeast Asia, and Borneo is the centre of their diversity. - Randi Agusti
LONDON (PA Media/dpa): Researchers have discovered a rare palm species found to flower underground.
Discovered by researchers at the Royal Botanic Gardens (RBG), Kew and partners, scientists have named the new-to-science species Pinanga subterranea, with its name coming from the Latin word for underground.
The plant is well-known to locals native to the tropical island of Borneo in South-East Asia, who like to snack on its bright-red, sweet and juicy fruit.
However, until now, the plant has remained unnoticed by scientists who, to date, have described around 300 different species of palm on the island.
William Baker, senior research leader at Tree of Life at RBG Kew, said: "I have been studying palms for 30 years and am amazed at how they continue to surprise us.
"This unexpected find poses many more questions than it answers. What is pollinating the palm? How does the pollinator find the flowers underground?
"How did this phenomenon evolve and what on Earth will palms surprise us with next?"
Pinanga subterranea joins more than 2,500 species of palm known to science, up to half of which may be threatened with extinction.
The palm can be found scattered across the primary rainforests of western Borneo, crossing state lines from Sarawak in Malaysia to Kalimantan in Indonesia.
Prior to its scientific description, the plant was known in at least three Bornean languages under the names of: Pinang Tanah, Pinang Pipit, Muring Pelandok, and Tudong Pelandok.
Despite being well-known to Borneo's indigenous people, P. subterranea has been entirely overlooked by the scientific community - highlighting the need to collaborate more closely with indigenous communities.
The researchers were first alerted to the plant's presence by study co-author Paul Chai, a Malaysian botanist and namesake of the palm species Pinanga chaiana.
He first encountered the palm in 1997 while he was brushing aside the thick leaf litter surrounding a young palm to take a better picture of it.
He noticed the fruit that had been revealed. There were several plants but only one with fruits.
In 2018, Kew scientists Benedikt Kuhnhauser, Peter Petoe and William Baker revisited Lanjak Entimau Wildlife Sanctuary and collected several specimens of the palm for scientific research.
Kuhnhauser, future leader fellow at RBG Kew, said: "Without the tip-off from our Malaysian colleague Dr Paul Chai, we probably would have mistaken this exciting new species for an unremarkable palm seedling and would have walked right past it.
"Instead, we have scientifically described an incredibly rare case of geoflory, that is underground flowering, and the very first known example of its kind in the entire palm family. It truly is a once-in-a-lifetime discovery."
Most flowering plants have evolved to develop their flowers and fruit above ground, which helps to facilitate pollination and the dispersal of seeds.
However, there is a small subset of plants that has evolved to flower and fruit underground - observed in 171 species across 89 genera and 33 plant families.
The study is published in the journal PALMS - the Journal of the International Palm Society.
