Anzia colpodes (aka “Black-Foam Lichen”)
Substrate: On hardwoods.
Habitat: In deciduous forests.
Description: Thallus foliose, forming rosettes of greenish gray, dichotomously branching, convex lobes, 1-2 mm wide, without soredia or isidia, lobes developing small, round lobules.
Apothecia: common, up to 5 mm in diameter, very concave.
Pycnidia: Usually buried in the tips of the lobes, seen as black dots.
Lookalikes: Anzia colpodes at first glance looks like a Hypogymnia, especially H. krogiae, but the lobes (apart from the hypothallus) are actually thin & solid. The two other North American species of Anzia are very rare. Anzia americana, a southern Appalachian species, is sorediate; A. ornata, on the southern coastal plain, is marginally isidiate.
Bibliography: Lichens of North America, by Brodo, Sharnoff, & Sharnoff
Database Entry: Distance Everheart 12-26-13