New cave-dwelling plant discovered

A new, and rare, species of nettle has been found in the limestone caves in China.

The species doesn’t grow in complete darkness but lives in very low light levels, sometimes with as little as 0.04 percent sunlight, deep within the cave. The team of botanists made the discovery while exploring a series of limestone caves and gorges in south west China. Two other species of nettle, entirely new to science, were also discovered in the deep gorges that run through the area. 

It is unusual to find a plant that can live in such low light levels, as the lack of sunlight and damp conditions in caves do not generally provide the right sort of conditions for plants to grow in. However, it is possible that caves could still provide a rich source of new species to science, as many are difficult to access and rarely visited by botanists.

“When my Chinese colleague Wei Yi-Gang from the Guangxi Institute of Botany first mentioned cave-dwelling plants to me, I thought that he was mis-translating a Chinese word into English,” says botanist and nettle expert, Alex Monro, from the Royal Botanic Gardens Kew, based in the UK. 

“When we stepped into our first cave, Yangzi cave, I was spell-bound. It had an eerie moonscape look to it and all I could see were clumps of plants in the nettle family growing in very dark condition.”

The three new species are described in the journal PhytoKeys. The discoveries were made as part of an expedition to find new plant species in the Guangxi Province of south western China. The area is known for its elaborate limestone caves, part of a geological feature known as ‘karst’ where the soluble limestone gets worn away over millennia by weathering. 

All three new species belong to a genus of Nettles known as Pilea. Scientists believe that there may be around 700 species worldwide, but up to one third have never been officially described or recorded in the scientific literature. The new species has been classified as vulnerable according to the IUCN Red List of endangered species.