This ancient lichen is a three-kingdom powerhouse that mimics human lung tissue

Gardening · Published 3 October 2026 Swipe more like this →

In short: Lobaria pulmonaria is not just a plant; it is a complex biological partnership between a fungus, a green alga, and cyanobacteria. This unique triple-kingdom organism, often called tree lungwort, has been used for centuries in traditional medicine, though its survival is now threatened by modern air pollution and forestry.

Lobaria pulmonaria is a foliose lichen defined by its intricate, leaf-like thallus that shifts from bright green when moist to a papery, brownish hue when dry. Its biology is a marvel of cooperation: it houses a green alga, Dictyochloropsis reticulata, alongside pockets of Nostoc cyanobacteria. These cyanobacteria, found in specialized structures called cephalodia, perform the vital task of nitrogen fixation, providing essential nutrients to the lichen. This complex symbiosis allows the organism to thrive in damp, old-growth forests, where it serves as a living indicator of forest health and age.

The lichen's common name, tree lungwort, stems from the doctrine of signatures—a historical belief that plants resembling human organs could treat the diseases associated with them. This led to its use in traditional remedies for respiratory issues, hemorrhages, and skin conditions across cultures from Italy to India and Canada. While these historical applications were based on appearance, modern science has begun to validate some of these claims. Research indicates that extracts from the lichen possess anti-inflammatory, antioxidant, and gastrointestinal-protective properties, likely due to the presence of various phenolic compounds and lichen acids.

Despite its resilience, L. pulmonaria is increasingly endangered, particularly in lowland Europe. It is highly sensitive to acid rain, which disrupts the nitrogenase enzyme in its cyanobacterial partners, effectively starving the lichen. Furthermore, its reliance on stable, old-growth environments makes it vulnerable to habitat loss and industrial forestry practices. Because it takes about 25 years to reach reproductive maturity, the species struggles to recover once its habitat is disturbed. Today, this ancient organism stands as a fragile reminder of the delicate balance required to sustain complex, multi-kingdom life in a changing environment.

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