Lecanora strobilina

Thallus continuous or dispersed, granular to irregularly subareolate, ± undelimited, uneven, white to white-yellow or pale yellow-green, surface not corticate and developing a pruinose coating of projecting crystals to 0.1 mm in length in dried specimens; prothallus inconspicuous. Apothecia to 1 mm diam., aggregated, sessile, the base slightly constricted; thalline margin entire to crenulate, finally excluded, not corticate, whitish-grey or sometimes concolorous with the thallus; disc flat to somewhat convex, grey-yellow to pale red-, orange- or grey-brown; epithecium colourless, often interspersed with colourless granular crystals; hymenium 35–55 µm tall; hypothecium with small granular crystals; paraphyses 1–1.5 µm diam., unbranched or sparsely branched, the apices not swollen. Asci 35–45 × 10–17 µm. Ascospores 10–13 (–16) × (3–) 3.5–4 (–5) µm, narrowly ellipsoidal and often somewhat reniform. Conidia ca 25 × 1 µm, curved. Thallus C–, K+ yellow to brown, KC± yellow, Pd–, UV+ pale orange [spot tests on European material are reported as all negative]; (usnic acid, ± zeorin, ± decarboxysquamatic acid).

A member of the L. symmicta group and thus a candidate for segregation into the genus Zeora Fr. (Ivanovich et al., in prep.). Most likely to be mistaken for C– chemotypes of L. symmicta which are separable by the corticate thallus and exciple that becomes excluded, the less strongly yellow colour (usnic acid absent), and the K/UV (wet)+ bright green-yellow fluorescence. Old dried specimens have a distinctive whitish, waxy appearance. Has a similar chemistry to L. compallens, but this is sorediate and is sterile.