

Flowers of a new species from the nettle family known only from caves, Pilea cavernicola, where it grows in very low light conditions. Photo by: Alex Monro.

The South China Karst region resembles a lost world with its stone forests and towering limestone formations that look like petrified skyscrapers. Standing at the edge of one of the region’s many vine-covered gorges, you could picture an apatosaurus lifting its head above the mist that blankets the gorge floor. Of course, that would be impossible, but what botanists recently found in the region was only slightly less surprising (to botanists). Near the back of a limestone cave, pink flowers bloomed on a newly discovered nettle that could survive on just a tiny fraction of the sunlight other plants receive. As Ian Malcolm in Jurassic Park said, “life will find a way.”

When botanist and nettle expert Alex Monro heard about the cave nettles from his Chinese colleague Wei Yi-Gang, he didn’t believe it.

“I thought that he was mis-translating a Chinese word into English,” Munro says. “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 botanists dubbed the new species Pilea cavernicola after the Latin for cave-dweller. In its subterranean lair, Pilea cavernicola only receives .04-2.78% the amount of full daylight. This feat of survival speaks to life’s tenacity and the endless versatility of evolution, but despite its hardiness, Pilea cavernicola is officially a vulnerable species according to the International Union for Conservation of Nature (IUCN). At present, scientists know the nettle from less than 200 mature specimens in only two locations—well within the IUCN’s criteria for vulnerability—but what is more disconcerting is the human threat Pilea cavernicola faces. Despite the Karst Region’s status as a UNESCO World Heritage Site, China continues to expand mining operations in the region. Farmers growing medicinal plants may also disturb the cave nettle by carving terraces right under its home.

But if the steep and unforgiving terrain of the Karst Region prove more vexing to developers, we may learn more about Pilea cavernicola‘s secrets of survival.



Botanists Wei Yi-Gang, Guangxi Institute of Botany, and Alex Monro, Royal Botanic Gardens Kew, standing within Yangzi cave with clumps of plants from the nettle family nearby. Photo by: Alex Monro.

CITATION: Monro AK, Wei YG, Chen CJ (2012) Three new species of Pilea (Urticaceae) from limestone karst in China. PhytoKeys 19: 51–66. doi: 10.3897/phytokeys.19.3968

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