This pinkish-white parasite grows in dense clusters looking like tiny gnome villages. It parasitizes fungi in the Rhizopogon genus, which form mycorrhizae with conifers. Networks of exploitation underground.
Alan Rockefeller, CC BY-SA 4.0, via Wikimedia Commons
A plant without chlorophyll
Hidden in the deep shade of mature conifer forests, Hemitomes congestum emerges from the forest floor as a fleshy, pink or cream-colored stalk. Commonly called the gnome plant, it reaches a height of only 2 to 10 centimeters. Unlike most plants, it has no green parts because it completely lacks chlorophyll, the pigment needed for photosynthesis. Its leaves are reduced to mere scale-like structures along the stem. The visible portion of the plant is the inflorescence, a dense cluster of flowers that appears for just a few weeks from early to mid-summer.
The gnome plant is a mycoheterotroph, meaning it derives all its nutrients from fungi. This adaptation allows it to thrive in the darkest parts of the forest where insufficient sunlight prevents photosynthetic plants from growing. The flowers themselves are bell-shaped and consist of four petals that are fused for at least half their length. The inside of the corolla is densely hairy, and a prominent yellow stigma sits at the center. After flowering, the plant produces a fleshy white berry. This fruit emits a strong musky or cheesy odor, which may attract small mammals to help disperse the seeds. Once the fruit ripens, the visible part of the plant withers away.
The underground heist
The gnome plant is the visible part of a complex relationship between itself, a fungus, and a conifer tree. It is an epiparasite, stealing energy that the tree provides to its fungal partner. The fungus, typically from the genus Rhizopogon, forms a beneficial mycorrhizal association with trees like Douglas-fir or pine. In this symbiotic exchange, the tree gives the fungus sugars produced via photosynthesis, and the fungus provides the tree with water and soil nutrients.
Hemitomes congestum hacks this system. It spends most of its life underground as a rhizome with fragile roots, tapping into the fungal network, or mycelium, to siphon off nutrients. It gives nothing back to the fungus or the tree. This strategy of parasitizing the mycorrhizal network has evolved independently around 40 times in the plant kingdom. Many of these specialized plants, including the gnome plant, belong to the family Ericaceae, the same family as blueberries and rhododendrons. The specific fungal species required for the gnome plant's seeds to germinate is still not precisely known, making its cultivation nearly impossible. This reliance on a very particular underground ecology contributes to the plant's rarity.
💡Fun Facts
The genus name *Hemitomes* translates to "half-eunuch," which may refer to one of its anthers containing no pollen.
After pollination, the plant's prominent yellow stigma turns black.
While its pollinators are not definitively known, the flower's hairy interior is thought to block small insects from stealing nectar, suggesting it is adapted for long-tongued insects like moths.
The fruit emits a pungent cheesy or musky smell, likely to attract animals to eat it and disperse the seeds.
