Garden Scientists Describe Rare New Species of Leafless Orchid

With such a strong contrast from a typical orchid, the other-worldly translucent pink stem and petals of this leafless species are certainly striking. In fact, João Farminhão was so struck by the beauty of the plant when he saw a photo of it, he went down a research rabbit hole learning all he could about it. This led to an unexpected discovery: the identification of a new species: Taeniorrhiza nguemae

Taeniorrhiza nguemae. Photo by Jean Philippe Biteau.

Taeniorrhiza nguemae 

Leafless orchids are exceedingly rare. This is especially true for epiphytic orchids, which grow on other plants, which make up the majority of the Orchidaceae family. In fact, only about 1 percent of epiphytic orchids lack leaves. 

Taeniorrhiza nguemae is only the second known species in the leafless genus Taeniorrhiza, which is characterized by plants with ribbon-like roots. Taeniorrhiza nguemae, notable for its dazzling pink and bright yellow flowers, is native to the rainforests of Gabon. 

Taeniorrhiza nguemae. Photo by Jean Philippe Biteau.

An eye-catching appearance 

Diosdado Nguema, a member of the Garden’s team in Gabon, first collected the specimen later identified as Taeniorrhiza nguemae while working  in the southwest part of the country. Its unique ribbon-like roots stood out to Nguema, part of a local field crew for the Smithsonian at the time. He collected a specimen without flowers in January 2015, and a flowering and fruiting plant two months later. Both were made into pressed specimens and cultivated in Libreville in a private garden famous for its large collection of African orchids. 

 Initially, scientists identified the plant as the long-lost Taeniorrhiza gabonensis, a species only collected once before in 1926. Photos of the plant appeared in Plantes à Fleures du Gabon, published in 2016, where they caught the eye of  Farminhão, a PhD student studying under Garden Scientist Tariq Stévart.  

As Farminhão read more, he was surprised that some of the details of the flowers in the photos didn’t match the description of Taeniorrhiza gabonensis. He looked at preserved flowers of the specimen in the Herbarium at Université Libre de Bruxelles, and compared them to scans of the reference specimen of Taeniorrhiza gabonensis.  

Based on the flower color, lip and spur shape, and size of Nguema’s collection, he concluded that it was not Taeniorrhiza gabonensis, or, in fact, any known orchid. 

“As a Garden employee, discovering and describing new species is part of my regular work, but it is not often that we find such an amazing species, combining beauty with scientific interest,” Stévart said. 

Taeniorrhiza nguemae. Photo by Jean Philippe Biteau.

A single origin of leafless orchids 

Farminhão shared his findings with Stévart. Subsequent DNA analysis confirmed the plant was a new species. DNA analysis also revealed that all tropical African leafless orchids in the Angraecum alliance native to Africa and Madagascar, have a single origin. 

The first epiphytic orchids in tropical Africa always had leaves, Farminhão explained, but 8.5 million years ago the ancestor of Taeniorrhiza evolved into a leafless plant, likely to resist drought.

“This evolutionary event happened only once in Africa and underlines the rarity of leaflessness among epiphytic orchids,” Farminhão said. 

Taeniorrhiza nguemae. Photo by Jean Philippe Biteau.

Critically endangered 

Taeniorrhiza nguemae is rare among orchids, and this unique beauty could disappear due to threats of deforestation from oil drilling in Gabon. Scientists preliminarily assessed the species as “Critically Endangered,” based on the IUCN’s Red List criteria. Illegal trade also poses a serious threat to genera of horticultural value such as  Taeniorrhiza

“Garden botanists and collaborators regularly make important discoveries as part of our global effort to document and conserve biodiversity, but spectacular finds like this one are special events, even for seasoned field botanists. They help to underscore the value of our work and provide motivation for continuing to push the boundaries of discovery into new areas,” said Pete Lowry, Director of the Garden’s Africa and Madagascar program. 

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