Plant of the Week

Wet Lobaria pulmonaria.
Lobaria pulmonaria (wet). The bright green color indicates that this lungwort lichen is saturated with water and pliable. Photo by Ralph Pope.

Dry Lobaria pulmonaria.
Lobaria pulmonaria (dry). When lungwort dries out, it is lighter in color. Dry lichens are very brittle and sensitive to disturbance. Photo by Karen Dillman.

Lungwort habitat.
Abundant growth of sun-tolerant lungwort. When shade lichens can grow in sunny environments, their pigment is generally darker in response to the light. Photo by Karen Dillman.

Lungwort, lung lichen (Lobaria pulmonaria (L.) Hoffm.)

By Chantelle DeLay

Lobaria pulmonaria is in the lichen family Lobariaceae (Kingdom Fungi). This species is found in North America, Europe, and Asia (no USDA PLANTS range map is available). Lungwort is usually found in humid forested areas with both conifers and hardwood trees. It can be quite common in its ideal habitat, quite literally dripping off trees and rocks. Lobaria pulmonaria occurs most often in shady environments and is an indicator for rich, healthy ecosystems such as old growth forests.

Lungwort is large, bright green, leaf-like lichen that grows on tree bark and mossy rocks. It has lots of ridges and lobes, creating a lettuce leaf or lung tissue appearance. Green algae give lungwort its bright green appearance. The underside of this lichen is pale with pockets of cyanobacteria (also known as blue-green algae) that are dark in color. Lungwort’s main method of reproducing is by granule-like masses of fungi and algae (called soredia) that form on the top surface of this lichen. These soredia break off and land on suitable surfaces, where they can grow into new lungwort lichens. Occasionally, lungwort will have spore-producing structures called apothecia that spread fungal spores. When combined with algae, these spores can grow into lungwort lichens.

Although lungwort’s main photobiont is a green alga, it is also a type of cyanolichen, which means that it contains nitrogen-fixing bacteria. When these lichens fall to the ground after a storm or wind event, they decompose into the forest floor, contributing their nitrogen reserve to the soil. There is much research with L. pulmonaria and other Lobaria species on their nitrogen contribution to the forest ecosystem of the Pacific Northwest and other parts of the United States. As with many other lichen species, L. pulmonaria is sensitive to air pollution. It cannot survive in polluted areas such as cities and other developed areas. Researchers use this species to gain information about air pollution in populated areas (see United States Forest Service National Lichens & Air Quality Database and Clearinghouse).

Uses for lungwort include dyes, teas, and wild animal forage. Because it resembles lung tissue, humans have used lungwort for lung ailments, such as tuberculosis and asthma. Large animals such as deer and moose, as well as small creatures like microscopic insects, use this lichen for food. Other critters like chipmunks and birds use lungwort, and other lichens, for nesting material.

For More Information

Lungwort in a shaded, moist drainage, on tree branches
Abundance of lungwort in shaded, moist drainage. These lichens are “dripping” off of tree branches. Photo by Chantelle DeLay.

Soredia on lungwort.
Granule-like masses called soredia line the ridges of this lungwort. Photo by Karen Dillman.

Plant of the Week

Decumbent Trillium (Trillium decumbens).
Decumbent Trillium (Trillium decumbens)