Lungwort lichen
A green, lettuce-like patch on old-growth trees that is three living things in one, and grows only where the air is clean.
Lungwort lichen at a glance
Lobaria pulmonaria LUNG-wort LY-ken; Lobaria pulmonaria is loh-BAIR-ee-uh pul-muh-NAIR-ee-uh
- Type
- Fungus · lichen
- Diet
- Producer
- Size
- Ridged green patches from about a hand's width to a dinner plate across, draped on trunks and branches.
- Lifespan
- Very slow-growing and long-lived, often decades and sometimes far longer.
- Conservation
- Not formally assessed globally by IUCN, but declining in many regions and used as a marker of clean air
A lichen is a partnership. A fungus builds the body and holds water, while algae and cyanobacteria living inside it make food from sunlight and pull nitrogen from the air. Together they feed the whole thing.
Is it safe to touch?
Harmless to touch. It is a great one to study up close, ridged and green when wet, papery and gray-brown when dry. Do not pull it off the tree, since it grows so slowly that it cannot easily replace what is lost.
On an old maple trunk in the Olympic rain forest, a ragged green patch swells and softens after rain, its ridges folded like the lining of a lung, which is exactly where the name comes from. It is lungwort lichen, and it is stranger than it looks. Three separate living things share this single patch, bound so tightly together that they act as one. A fungus builds the body and holds the water. An alga tucked inside makes food from sunlight. And a third partner, a nitrogen-fixing bacterium, pulls fertilizer straight out of the air. None of them could make this patch alone. Together they make a life.
That partnership has one strict requirement, and it turns the lichen into a kind of test. Lungwort only grows where the air is clean. Pollution poisons it, so where the air has gone bad it simply vanishes, and where it thrives you can trust that the forest is breathing clean. Scientists read it exactly that way, walking the woods and noting where the green lettuce grows and where it has gone, using a living thing as an air-quality meter that never needs batteries.
Come back to the same patch on a dry day and you might think it died. Without water it curls papery and gray-brown against the bark, dull and brittle, looking finished. It is only waiting. Splash a little water on it, or wait for the next rain, and within minutes it swells, softens, and greens back to lettuce, alive again as if nothing happened. Three creatures in one skin, growing only in clean air, playing dead through the dry spells and coming back with the rain.
Did you know?
- It is not one living thing but three, a fungus, an alga, and a nitrogen-fixing cyanobacterium, all living together as a single lichen.
- It only grows where the air is clean, so scientists use it as a living air-quality meter. Where the air is polluted, it disappears.
- When it dries out it turns papery and gray-brown and looks nearly dead, then greens up and softens within minutes of getting wet again.
Common questions
Is lungwort lichen a plant?
No. It is a lichen, a partnership of three living things: a fungus that builds the body, an alga that makes food from sunlight, and a bacterium that pulls nitrogen from the air. Together they act like one organism.
Why do scientists watch lungwort lichen?
Because it only grows where the air is clean. If the air becomes polluted, lungwort vanishes, so its presence or absence works like a living meter for air quality.
Why does it look dead sometimes?
When it dries out it turns papery and gray-brown and seems lifeless. Add water and within minutes it greens up and softens again. It was only waiting for moisture.