Lazy Cheating Plant Lives Underground, Outsources Photosynthesis to Fungus

The flower of the Sciaphila yakushimensis (left) and that of its close relative Sciaphila nana. Associate professor Suetsugu Kenji

Visit Yakushima, Japan, and you'll encounter the subtropical island's most popular attraction — an ancient forest of craggy cedar trees with massive trunks that reach more than 16.4 feet (5 meters) in diameter. Don't spend all your time looking up into the leafy canopy, though. There's likely to be a plant at your feet that's just as interesting

Thanks to one observant Japanese scientist, we now know the area is also home to one of the world's smallest — and and most unique — parasitic plants. In October 2015, Suetsugu Kenji, a project associate at the Kobe University Graduate School of Science, canvassed the island for plant specimens with photographer Yamashita Hiroaki. In the process, Kenji came across a diminutive and unfamiliar plant.

The newly discovered plant Sciaphila yakushimensis is observable above ground only when it flowers or fruits.
Associate professor Suetsugu Kenji

Kenji suspected the plant — just 5 centimeters (1.97 inches) in height with cabernet-colored stems and buds — was a mycoheterotrophic plant, so he collected it for further examination. Mycoheterotropic, or parasitic plants, get their name from the unusual way they obtain nutrients. They basically outsource photosynthesis to a fungus.

Most plants rely on photosynthesis, a process by which they transform energy from the sun into chemical energy that serves as a nutrient source. The parasitic plant collected by Kenji doesn't need photosynthesis to survive. It evolved in such a way that it obtains all its water, minerals and carbohydrates from fungi — in this case, the plant's root system takes what it needs from fungi on ancient tree roots, even if the roots are all that remain in now-deforested areas. It's a symbiotic relationship known as mycorrhizae.

The ability of plants like the newly identified Sciaphila yakushimensis (named for where it was found and described in the February issue of Journal of Japanese Botany) has been one of the most intriguing and secretive processes in botany's history. Researchers determined it was related to the plant Sciaphila nana, an above-ground plant. The only time the newly discovered plants grow above ground is when they briefly flower or fruit, making it exceedingly difficult to find or study them.