The flowers of Sciaphila yakushimensis (left) and Sciaphila nana poke above the ground Suetsugi Kenji

It’s a low-down, dirty cheat. A newly discovered Japanese plant spends most of its life hidden underground and steals nutrients from fungi rather than getting its energy from the sun.

Kenji Suetsugu of Kobe University came across the previously unknown plant in an evergreen forest on the subtropical Japanese island of Yakushima while documenting other fungi-parasitising – mycoheterotrophic – plants in Japan.

The plant’s stem is about 3-9 centimetres long and has between nine and 15 purple star-shaped flowers, which push up above the ground. Suetsugu has named it Sciaphila yakushimensis after the island.


The plant can’t photosynthesise and, like other mycoheterotrophs, steals the carbon it needs from a fungal host. The parasitic plant attracts strands of mycorrhizal fungus into its many hairy roots and then feeds off fungus growing inside the roots.

Life in the dark

Its parasitic lifestyle is an adaptation to the forest understorey, where the sun’s rays struggle to penetrate and so photosynthetic plants are rare, says Suetsugu.

Because it doesn’t rely on photosynthesising the sun’s light for its energy, it can stay underground, reducing the risk of being eaten by aboveground herbivores. It only pokes through the leaf litter to flower and fruit.

Vast fungal networks in the forest soil are linked up with plant roots and usually get their carbon from trees, in exchange for water and minerals that their tiny hairs extract from soil.

But mycoheterotrophs taps into this network and get the carbon from fungi, which got it from other plants to start with.

“These mycoheterotrophs are extremely rare and could not survive without a flourishing forest, sustained by species-rich underground fungal networks,” says Suetsugu.

Rare but not protected

Given that it only seems to have two small populations, the new species can be considered critically endangered, Suetsugu says. Other mycoheterotrophic plant species have recently been found in the area, but many are not yet officially protected.

Such plants are dependent on their host fungi, so Suetsugu says it will be necessary to conserve entire ecosystems to protect these rare plants. He recommends that regulators should restrict logging and construction to preserve these and other endemic species in the forest habitats of Yakushima.

Constantijn Mennes at the Naturalis Biodiversity Center in Leiden, the Netherlands, says there is still a substantial amount of undescribed biodiversity, even in flowering plants.

“This observation adds to a large list of critically endangered mycoheterotrophic species, like species of Kupea and Kihansia in Africa,” he says.

Journal reference: Journal of Japanese Botany, Vol. 91 No. 1

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