Lecidea turgidula

Thallus effuse, immersed or thinly granular, whitish to grey, often inconspicuous. Apothecia 0.2–0.6 (–0.8) mm diam., black, with bluish bloom when wet, sometimes thinly white-pruinose, sessile or (on wood) partly immersed, flat to convex; true exciple excluded, usually of coherent (in K) radiating hyphae, colourless to darkish greenish or brownish, I± pale violet; epithecium brownish to blue-green, K± green intensifying, N+ reddish, also with minute pale granules that dissolve in K; hymenium 30–40 (–50) µm tall, streaked violaceous (K+ green) or brownish to greenish (K+ intensifying); hypothecium colourless; paraphyses 1.3–2 µm diam., sparingly branched and anastomosed, the apices scarcely swollen but sometimes with a dark brownish hood to 5 µm diam. Asci 25–30 × 10–13 µm, Bacidia-type. Ascospores 6–10 (–14) × 2.5–4.5 (–6) µm, 0(-1)-septate, narrowly ellipsoidal to cylindrical, sometimes slightly curved. Pycnidia ca 100 µm diam., black, ± immersed in the substratum, the wall green-brown, K+ green intensifying; conidiogenous cells in chains, subcylindrical; conidia arising laterally and terminally, 3–3.5 × 1.5–1.8 µm, bacilliform. Thallus C–, K–, KC–, Pd–, UV– (placodiolic acid).

Sometimes mistaken for a Micarea (e.g. M. olivacea), but distinguished from that genus by the exciple of coherent hyphae, and minute granules in the epithecium that give the apothecia a pruinose appearance (bluish bloom when wet). Schmull et al. (2011) showed that this species and L. leprarioides occupy a well-defined clade within the Lecanoraceae; a new genus would probably be justified but this has not yet been introduced.