Thanks to researched DNA, they finally know where this plant belongs in the tree family tree and gave it the name ‘Mystery of Manu’.

In 1973, a scientist stumbled upon a strange tree in the Amazon rainforest unlike anything he’d ever seen. The tree was about six meters high and bore small orange fruits in the shape of Chinese lanterns. The scientist collected samples of the leaves and fruits and showed them to colleagues, but no one could identify this mysterious plant. Until now. Because fifty years later, the plant’s personality crisis has finally been resolved.

no one knows

“When I first saw this little tree, the fruit in particular caught my attention,” recalls Robin Foster, the scientist who originally collected the enigmatic plant in Peru’s Manu National Park. “I didn’t really think it was special, except that it had properties of plants from different plant families and didn’t fit neatly into one family. Usually I can see the family at a glance, but I couldn’t with this one.” Foster wasn’t the only one who didn’t know. Botanist Nancy Hensold, who came across a dried specimen more than thirty years ago, couldn’t figure it out after several frantic attempts. “It really bothered me,” she says.

A photo of the mysterious tree in the Amazon rainforest. Image: Patricia Álvarez-Loayza

The mysterious plant then sat on the shelf in the Field Museum for years, although no one had forgotten it. Finally, a research group was awarded a grant to re-study the plant, and the search for the plant’s identity was reborn.


The team attempted to analyze the plant’s DNA using dried specimens. When that didn’t work, an expedition led by scientist Patricia Álvarez-Loayza was launched to search for fresh specimens in the Peruvian park. In the end, the researchers managed to analyze the tree’s DNA. And it leads to a very surprising discovery. Thus, the closest relatives of the mysterious plant to the Picramniaceae to belong, while the plant itself does not exactly resemble it at first glance. “Given its general characteristics, no one would have placed it in that family,” Hensold said.


Because nobody really could believe it, the help was called in from Wayt Thomas, a Picramniaceae-expert. “Although he was also quite surprised at first, he dug further. “I decided to take a closer look,” he says. “And when I looked at the small, 2-3 millimeters long flowers, the puzzle pieces fell into place.”


Now that DNA testing has finally revealed which family the plant belongs to, the researchers were also able to give it a formal scientific name. The plant is up to Aenigmanu alvareziae baptized. The genus name Aenigmanu means ‘mystery of Manu’, while the species name honors Patricia Álvarez-Loayza, who collected the first specimens used for genetic analysis.

To protect

Not only has this study resolved the plant’s personality crisis, it also has very important implications. The researchers argue that obtaining a scientific classification for Aenigmanu alvareziae can help protect the Amazon rainforest from deforestation and climate change.

“Plants are generally underexposed,” Foster says. “And especially plants that live in the upper part of the Amazon. To understand the changes in the tropics, to protect what remains and to restore areas that have been wiped out, plants are the foundation for everything that lives there. It is therefore very important to study them. The best way to organize information about plants and draw attention to them is to give them unique names. A single rare species on its own may not be important to an ecosystem. But together they tell us what’s happening out there.”