Thallus:  Foliose, consisting of paper-thin flat or slightly concave, unbranched scales with lobed margins, tightly attached to the bark except at the margin.  Young thalli shiny; older ones roughened.  Upper surface brown, bronze, olive-brown, or dark brown when dry, becoming paler and greenish when wet.  Lower surface olive at the margin but darker elsewhere, brown to blackish, because covered by dark brown rhizines ( Fig. A ).

Apothecia: Rare

Soredia: Sometimes present.  Usually developing at the tips of the isidia.

Isidia:  ( Fig. B ) Consisting of minute, brown, finger-like projections from the upper surface of older thalli.  ( Use a hand lens. )

Comments: The brown color; small, foliose thallus; and minute isidia distinguish this species.  Parmelia subaurifera is common and widespread, and because it is relatively tolerant of pollution,  it is found in all but the dirtiest areas.