Gloeoheppia turgida

Gloeoheppia turgida is a species of gelatinous lichen in the family Gloeoheppiaceae.^[2] The species forms small scaly lobes up to 4 mm across that become strongly swollen and convex, with a dark olive to greenish-black upper surface that may carry a thin white powdery coating. It occurs in Mediterranean Europe and North Africa, where it grows on muddy ground with its tightly crowded and contorted lobes giving the lichen a distinctly pleated or wrinkled appearance.

The species was first described by the Swedish lichenologist Erik Acharius in 1810, as Endocarpon turgidum. He based the species on Swiss material gathered on muddy ground by Johann Christoph Schleicher. In his diagnosis Acharius emphasised a thick, leathery, lobed brown thallus covered with a bluish pruina; a powdery-to-spongy underside; and irregular, blunt lobes that are somewhat inflated, flexuous and intricately folded. When moistened, the thallus turns a dark brown. Because the lobes are tightly crowded and contorted, the lichen appears swollen and strongly pleated or wrinkled. He also noted that the ostioles (openings) of the perithecia begin as minute convex points and, with age, become small, urn-shaped structures immersed in the thallus and scarcely marginate; according to Acharius, these were features that, together with the pruinose surface and overall thallus form, separated this species from others in its genus.^[3]

Vilmos Kőfaragó-Gyelnik reclassified the species in Gloeoheppia in 1935.^[4]

Gloeoheppia turgida has a squamulose (scaly) thallus made up of small, leaf-like lobes. These squamules are round to elongate and lobulate, sometimes overlapping, and become strongly convex and swollen, reaching up to about 4 mm across. Their margins curve downwards and are often rolled under, and the thallus is anchored to the substrate by coarse fungal hyphae. The upper surface is smooth and dark olive to greenish black, becoming paler in shaded situations, and may carry a thin white, powdery deposit (a pruina); it is covered by a relatively thick layer of dead tissue. The underside is smooth, olive to pale flesh-coloured and lacks a differentiated cortex. The medulla contains an algal zone that extends through most, or sometimes all, of its depth; where a lower algal-free zone is present it consists of tightly packed, paraplectenchymatous fungal cells.^[5]

The species does not form vegetative propagulesuch as isidia or soredia. Sexual reproduction takes place in apothecia (fruiting bodies) that are produced several to a lobe and are immersed in the thallus, with exposed discs up to about 0.3 mm in diameter. Each ascus contains eight ascospores, which are ellipsoid and measure about 12–18 by 5–8 micrometres.^[5]

Gloeoheppia turgida occurs in Mediterranean Europe and North Africa.^[5]