Researchers at the Royal Botanic Gardens (RGB), Kew and their partners have found what is described as the only known member of the palm family which flowers and fruits almost entirely underground. The findings of the study were published in the journal PALMS on Monday. Given the plant’s unique characteristics, researchers have named the new-to-science species Pinanga subterranea, which means ‘underground’ in Latin.
Where was the plant found?
The plant and its fruit are native to the tropical island of Borneo in Southeast Asia where it is well-known to locals, some of whom even consume the bright-red fruit which is said to be sweet and juicy.
However, P.subterranea was overlooked by scientists for years now, who have found some 300 different species of palm on the island. The plant is known in at least three Bornean languages under the names, Pinang Tanah, Pinang Pipit, Muring Pelandok, and Tudong Pelandok, by the locals.
The international team of researchers said that the plant can be found across the primary rainforests of western Borneo and scattered across the borders from Malaysia’s Sarawak to Indonesia’s Kalimantan.
Need for collaboration
According to researchers, the plant was hiding in plain sight and has been overlooked by the scientific community for years now.
“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,” said Dr Benedikt Kuhnhäuser a future leader fellow at RGB, Kew, who was also a part of the research team.
He added, “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.”
What makes the plant so unique?
While a majority of flowering plants have evolved to develop their flowers and fruit above ground since it helps with pollination and the dispersal of seeds, there is a small subset of plants that have evolved to carry out this process underground.
Therefore, P.subterranea not only joins the more than 2,500 species of palm (that the scientists know about so far) but also at least 171 species across 89 genera and 33 plant families, which are known to flower and fruit underground through the process of geoflory and geocarpy, respectively.
However, P. subterranea is a case of a dual instance of geocarpy and geoflory, which has been all the more baffling for the researchers since the Pinanga genus is typically pollinated by insects and cannot move around as easily below ground as above.
The international team of scientists found a high number of seeds and fruit set by the plant which indicates that there has been a successful pollination mechanism which remains unknown to the researchers.
“I have been studying palms for 30 years and am amazed at how they continue to surprise us,” said Dr William Baker, senior research leader at Tree of Life at RBG Kew.
He added, “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?”
Not the first discovery
It is also worth noting that while the recent team of international scientists collected specimens and ascertained that the species was new to science, Agusti Randi, an Indonesian researcher from the National University of Singapore and lead author of the study conducted had also encountered a couple of specimens of the palm back in 2017.
According to Randi’s study, at least one of the samples collected appeared to have been dug up by wild pigs while others were most likely eaten or crushed by the animals.
“The first time I encountered this dwarf palm in 2017 in a forest in West Kalimantan, a group of wild boars were digging in the soil around a population of P. subterranea, and I found several ripe fruit with a striking, bright red colour lying on the ground,” said the lead author about the findings.