Powdery Shield Lichen
Physcia millegrana
Dusted in Light and Air
Tiny, pale green-gray rosettes spreading like powder across bark and twigs.
The Powdery Shield is among the most common foliose lichens in temperate forests, thriving where air is clean and light abundant.
Powdery Shield and Candleflame Lichen
A mixed lichen community.
The pale gray Physcia millegrana forms powdery shields above the lemon-yellow Candelaria concolor, both anchored to a red maple twig.
Size: 5112x3410
Camera: Canon EOS 5D Mk IV
Lens: EF100mm f/2.8L Macro IS USM
Settings: ISO 400 • Aperture f/5.6 • Shutter 1/250 s
Description
The Powdery Shield forms tiny overlapping lobes, giving a frosted or dusty appearance.
The upper surface is gray-green and often dotted with fine white soredia — powder-like granules used for reproduction.
This species prefers nutrient-balanced, clean air and often appears alongside Candelaria concolor or Physcia aipolia on bark and branches.
Thallus type: Foliose (leaf-like, loosely attached)
Color: Gray-green to pale olive
Surface: Dusted with soredia; lacks fruiting discs
Habitat: Bark of hardwoods, fence posts, and occasionally rock
Indicator value: Sensitive to air pollution; presence indicates good air quality
Powdery Shield — Physcia millegrana
Fine, powder-dusted gray rosettes.
Minute foliose clusters spread thinly across bark, forming a pale gray mat with a frosted texture. Sensitive to air quality, this lichen thrives in clean, open environments.
• Size: 5112x3410
Common Greenshield — Flavoparmelia caperata
Broad, leafy lobes with pale green hue.
A larger foliose lichen forming circular patches with wrinkled, overlapping lobes. Its surface becomes more vivid when moist, contrasting the Powdery Shield’s subtle tones.
• Size: 6240x4160
Photographer’s Perspective
The pairing of Candelaria concolor and Physcia millegrana captures a subtle narrative —
two lichens sharing light and surface, each revealing a different tone of resilience.
The composition balances color and texture: Candleflame’s warmth and Powdery Shield’s calm neutrality.