New Zealand botanists are warning the public not to consume lichens that grow on shady trails and rocks across the country, after misleading stories about its stimulating properties have quickly spread online.
The lichenologist of the University of Otago, Dr. Allison Knight, nicknamed a common species of local lichen "sexy sidewalk lichen" after discovering that it was promoted as a natural alternative to Viagra in online markets, especially in China.
The scientific name of the plant is Xanthoparmelia scabrosaand although it may have some properties similar to Viagra, Knight said, it can also be "quite toxic".
The lichen found on the trails can also be contaminated by pollutants from the city center such as urine and dog droppings, car exhaust, arsenic, mercury and lead.
The lichen in question is a species that grows only in New Zealand and the Pacific, most often in urban areas, and there are hundreds of products that sell it in the form of pills and powder in the Chinese online Alibaba market, retailing for a value between 12 and US $ 300 per kilogram.
Knight stated that most of the products available online are composed of 80% Viagra and 20% cut grass. To his knowledge, rigorous tests have not been conducted on "sexy pavement" lichen to prove its efficacy or safety for human consumption.
Knight's ironic name for the species was adopted by the inaturalist website, a popular global scientific initiative of the California Academy of Sciences and the National Geographic Society that describes itself as a place to "identify plants and animals".
"It has never been really tested and is quite toxic, so it is not recommended to consume it. But it is a precursor to Viagra, although large quantities could actually be very harmful," Knight told the Guardian.
New Zealand botanist Dr. Peter de Lange has also mocked the plant's therapeutic qualities, telling the Newsroom website that its effect on sexual function may be as opposed to what was hoped for.
But Knight said that lichen could have enormous health benefits. "It [Xanthoparmelia scabrosa] it does not occur all over the world, it does not even occur in China where all these enormous quantities come from. But lichen has enormous potential and there is a lot of research going on to see how it can be used for the next generation of antibiotics to replace even those we're becoming resistant to. "
There are at least 20,000 varieties of lichens known around the world, 2000 of which grow in New Zealand, particularly on shady paths, trunks of fruit trees and in native forests. Like much of New Zealand's unique flora, some varieties and species of lichens are now endangered or threatened.
"It's nice to focus people's attention on lichens, I always say they are hidden in full view," said Knight
"They tend to be undervalued and underestimated. They are undervalued and are very important because they are the colonizers: they are the first things that will colonize bare rock. When life came out of the ocean … it was lichen."