Icmadophila
Lichens containing a trebouxioid alga; thallus crustose, squamulose or small-foliose, generally pale green, pale grey, pastel blue-green, or whitish, sometimes sorediate, isidiate or schizidiate; apothecia opaque pink, pink-orange or whitish, often pruinose, with a non-algal rim that may recede with maturity, this formed of tangled hyphae, often also with a thalline rim clinging to the sides; hymenium formed moderately to densely branched and anastomosing paraphyses embedded in gel; hypothecium colourless; asci cylindrical or narrowly clavate, with a thin IKI+ dark blue tholus; spores 8 per ascus, colourless, 1-3 septate, fusiform, thin-walled.
References: Purvis et al. 1992.
Icmadophila ericetorum (L.) Zahlbr.
Thallus pale blue-green or greenish white, granular, warty or smooth, often with bits of the upper layers breaking off (schizidia), often covering very large areas (up to 1 m wide); apothecia 0.5-4 mm wide, pale pink or orangish pink, with a prominent rim that recedes with maturity, usually pruinose; spores 8-12 per ascus, elliptic or spindle-shaped, 1- to 3-septate, 13-24 × 4-8 µ.
Reactions: K+ yellow-orange, KC+ orange, PD+ orange, UV+ blue-white.
Contents: Perlatolic and thamnolic acids.
Habitat: On decaying wood, bark or mosses/liverworts, usually on logs, always on or near the ground. All forested elevations.
Similar Species: No other species in our area has an extensive pale blue-green thallus in combination with pale pink, unstalked apothecia. Baeomyces rufus is somewhat similar but has stalked apothecia.
Local Status: Common.