R. Fraley

Flavopunctelia soredica

Flavopunctelia soredica

Family: Parmeliaceae

Powder-edged Speckled Greenshield (Flavopunctelia soredica) is a pale yellow-green to gray-green foliose lichen notable for abundant white pseudocyphellae (speckling) and powdery soralia concentrated along lobe margins. It commonly colonizes hardwood bark and contributes to mixed-species bark mosaics in a range of light exposures.

For representative images and visual context, see the Gallery page: Powder-edged Speckled Greenshield.

Description

Flavopunctelia soredica is recognized by:

  • Growth form: Foliose, forming loose rosettes or irregular patches
  • Thallus: Pale yellow-green to gray-green; generally flat to slightly convex
  • Lobes: Broad, rounded, often slightly overlapping
  • Surface features: Abundant white pseudocyphellae (speckling) scattered across the upper surface
  • Soralia: Powdery, white, typically concentrated along lobe margins
  • Underside: Dark brown to black with simple rhizines

Apothecia are uncommon; vegetative reproduction by soredia is the primary means of dispersal.

Substrate and Habitat

Typical substrates and settings include:

  • Hardwood bark (elm, maple, ash, oak)
  • Twigs and small branches
  • Urban trees, parks, and open woodland where light is available

Notes:

  • Prefers well-lit bark exposures but tolerates a range of moisture regimes.
  • Often found in mixed communities with foliose Physcia, Flavoparmelia, and crustose species.

Identification

Key features for field diagnosis:

  • Color: Pale yellow-green to gray-green
  • Form: Loose, foliose patches or rosettes
  • Surface: Distinct white pseudocyphellae; margin-focused powdery soralia
  • Underside: Dark, with short, simple rhizines
  • Reproduction: Abundant soredia; apothecia rare

Distinguishing from Similar Species

  • vs. Flavopunctelia flaventior: Compare soralia distribution and pseudocyphellae density; local notes may apply.
  • vs. Flavoparmelia caperata (Common Greenshield): F. caperata is smoother and more inflated, lacking white pseudocyphellae.
  • vs. Physcia millegrana (Powdery Shield): P. millegrana has much smaller lobes and an overall uniformly powder-dusted surface rather than strong marginal soralia.

Ecology and Notes

Indicator value: Moderately tolerant of urban conditions; presence indicates established bark communities and tolerates some air impurity compared with more sensitive species.

Distribution: Widespread in temperate North America on hardwoods; frequency varies regionally.

Reproductive strategy: Vegetative reproduction via soredia is common; sexual structures are uncommon in field populations.

References