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DescriptionLife habit: lichenized; Thallus: foliose, dwarf-fruticose, squamulose peltate or crustose, few mm to few cm wide; gelatinous when wet; thallus surface: blackish, usually dull, rarely glossy, dark olive when moist, very rarely grayish pruinose, smooth, plane to uneven, rarely folded and plicate, sometimes with globose isidia; thallus anatomy: ecorticate, very rarely homoiomerous with paraplectenchymatous or reticulate hyphae, usually heteromerous with a loose or compact, sometimes fountain-like central hyphal strand and with reticulate hyphae surrounding the photobiont cells at the thallus margins; photobionts: chroococcoid cyanobacteria, secondary photobiont absent; Ascomata: absent or present, apothecioid, thallinocarpous, laminal, marginal or terminal, orbicular or irregularly shaped, immersed to sessile, rarely almost stalked, margin present but often indistinct, with thalloid rim; ontogeny: hemiangiocarpous, ascogonia single or in groups, arising freely beneath the thallus surface, tangle of generative hyphae lacking; disc: covered by small packets of thalline tissue; or: partial hymenia laterally separated by intrusions of sterile thalline tissue, partial hymenia opening by small punctiform "discs" breaking through the thalline cover; exciple: usually lacking or very thin and surrounding distinctly separated partial hymenia, epihymenium: lacking,; hymenium: continuous or discontinuous and sometimes separated into roundish partial hymenia, IKI+ blue turning radiply reddish brown or wine red; paraphyses: sparse, septate, sparsely branched and anastomosing, with hardly thickened terminal cells; asci: irregularly shaped, ±cylindrical to clavate or obclavata, prototunicate, wall thin, not amyloid, (8-)16-32-spored; ascospores: hyaline, simple, ellipsoid, 5-7.5 x 2.5-5 µm, thin-walled; Conidiomata: pycnidial, laminal or marginal, immersed, globose to broadly pyriform or ellipsoid; conidiophores: simple, cells elongated; conidia: ellipsoid, fusiform or bacilliform, 2.5-5 x 1-2 µm, acrogenous; Secondary metabolites: not detected; Geography: primarily from arid to temperate regions in the Northern Hemisphere; Substrate: on various dry rocks including mortar, rarely on soil crusts.; Notes: The presence of thallinocarpous fruiting bodies, the polysporous, irregularly shaped asci, and the hymenial reaction in IKI (blue, rapidly turning red) are characteristic. The fountain-like hyphal arrangement in fruticose thalli with ±round or slightly flattened lobes is typical for the species of the genus in the original sense. On the other hand, Gonohymenia was used to accommodate crustose, squamulose, peltate and foliose-fruticose species with various types of thallus anatomy. Moreno and Egea (1992) united Lichinella and Gonohymenia based on similarities in the thallinocarpous fruiting bodies, as well as ascus characteristics. Consequently, Lichinella in the wider sense contains lichens of various growth forms with different thallus anatomies. The term "thallinocarp" refers to a type of fruiting body exclusively found in the genus Lichinella (including Gonohymenia). Thallinocarps are indistinct swelling concolorous with thallus. The "disc" is rough or dotted, and the hymenium is continuous or distcontinuous but covered by patches or a continuous layer of sterile thalline plectenchyma. Sometimes the "hymenium" becomes separated into small, "partial hymenia".