Common Greenshield Lichen

Scientific name - (Flavoparmelia caperata)

The pale, leafy lobes and black-veined underside identify them as Common Greenshield Lichen (Flavoparmelia caperata) — one of Minnesota’s most widespread bark lichens. This elm tree has several round, greenish patches on the trunk.

Lichens do not have roots; nutrients are extracted from the air, making them sensitive to air quality. Their presence indicates clean air and healthy forest conditions, thriving especially in shaded or semi-open habitats.

Identification

• Color: Pale green to yellowish-green, turns brighter when wet.
• Form: Foliose (leaf-like) with broad lobes, slightly wrinkled surface.
• Underside: Black with pale veins and short rhizines.
• Substrate: Elm bark — medium texture and neutral pH support good lichen growth.
• Air Quality Indicator: Abundant presence suggests healthy, low-pollution air.

Photos

Flavoparmelia caperata forming a circular colony on elm bark. Yellow crustose lichens visible nearby.

Close view showing the wrinkled, overlapping lobes with a slightly glossy texture.

Two mature colonies of F. caperata on an elm trunk in a mixed deciduous forest.

Habitat

Found in a quiet stand of mixed hardwoods with scattered elm, oak, and maple.
Moist fall weather and shaded conditions likely helped preserve vivid color and texture.

Field Notes

• Date: October 24, 2025
• Location: Near Lakeville, MN
• Weather: Cool and sunny — ideal for photographing lichens.
• Equipment: Canon DSLR with macro lens and zoom lens, tripod mount.

Fun Fact

Flavoparmelia caperata produces caperatic acid, which helps protect it from microbial damage and UV exposure — one reason it can live for decades on the same trunk.

See also: Minnesota Lichen Guide

Observation and photography by Ray Fraley

References

[Common Greenshield Lichen, Missouri Department of Conservation]https://mdc.mo.gov/discover-nature/field-guide/common-greenshield-lichen