Candelaria concolor

Family: Candelariaceae

Candleflame (Candelaria concolor) is a small, vivid yellow foliose lichen forming scattered patches or loose clusters on tree bark. Its powdery surface and soft, glowing color give it a flame-like appearance, especially noticeable in winter or under moist conditions.

This page documents field observations used for identification. Visual presentation and artistic interpretation are handled separately in the Gallery section, Candleflame.

Description

Candelaria concolor is recognized by:

Growth form: foliose to weakly squamulose
Thallus: bright lemon-yellow to yellow-orange, thin and delicate
Lobes: very narrow, ribbon-like, often irregular or poorly defined
Surface features: densely sorediate; soredia fine and powdery, covering most of the upper surface
Underside: pale to white
Rhizines: simple, white, sparse to moderately developed
Attachment: loosely attached

Colonies are typically small and fragmented, often appearing as scattered flecks rather than continuous rosettes.

Substrate and Habitat

Typical substrates and settings include:

Bark, especially hardwoods
Occasionally on decaying wood

Habitats include open woodlands, forest edges, and urban trees. The species tolerates a wide range of light conditions and is often abundant in nutrient-enriched environments.

Identification

Key features for field diagnosis:

Color: bright, uniform yellow
Form: small, delicate foliose patches
Surface: strongly powdery due to dense soredia
Underside: pale with simple white rhizines
Reproductive structures: apothecia rare or absent
Chemistry: typically not required for identification

The combination of fine powdery soredia, very narrow lobes, and small thallus size reliably separates Candelaria concolor from larger yellow foliose lichens.

Ecology and Notes

Candelaria concolor is often one of the first yellow lichens to colonize young or disturbed bark surfaces. Its small size and delicate structure make it easy to overlook unless viewed closely. Colonies may persist as scattered patches rather than expanding into large, cohesive thalli.

Research Grade observations are common across Minnesota, reflecting the species’ tolerance of a range of environmental conditions.

References

Consortium of North American Lichen Herbaria
iNaturalist — Candelaria concolor
Brodo, I. M., Sharnoff, S. D., & Sharnoff, S. Lichens of North America