Trapeliopsis flexuosa

Thallus greenish grey to grey-green or white to dark blue-grey, of scattered to crowded, uneven granular areoles; areoles 80–250 µm diam., but scattered or marginal areoles often ± flattened and effigurate and up to 400 µm diam.; soralia 200–400 µm diam., at first discrete, sometimes becoming confluent; soredia farinose to finely granular, grey-green to dark blue-green. Apothecia 0.2–0.7 mm diam., dark green- grey to green-black, rarely pale or pinkish (in extreme shade), flat to slightly convex; hymenium 40–50 µm tall; asci 30–50 µm in length. Ascospores 7–9.5 × 2.5–4 µm. Thallus C+ red, K–, KC+ red, Pd–, UV+ whitish (gyrophoric acid).

Resembles Trapeliopsis granulosa which has larger ascospores however, both species are normally sterile in which case, T. granulosa can be separated by  colour differences (± paler grey and lacking dark green of blue tinges) along with larger areoles (20–500 µm diam), without scattered marginal areoles. Trapeliopsis flexuosa has areoles 80–250 µm diam., with scattered marginal areoles  to 0.4 mm diam. Diminutive morphs can resemble Micarea coppinsii which has smaller algal cells.