Gymnographopsis forms a dull grey-olive to yellow-brown crust (thallus) that lacks a true cortex and is often dusted with minute beige crystals. The ascomata are straight to weakly curved lirellae (0.2–1.5mm long) whose lips soon open to expose the disc; their flanks may appear brown-black but are only partly carbonised . A light brown excipulum overhangs the clear hymenium, which is free of inspersion and lined with short, smooth periphysoids . The Graphis-type asci usually contain eight hyaline ascospores that become conspicuously muriform—divided by numerous transverse and a few longitudinal septa—yet remain iodine-negative (I–); spore sizes in most species fall between 20 × 7μm and 40 × 12μm, though extremes occur. Chemistry is modest: norstictic acid is frequent, with stictic-series depsidones or no detectable metabolites in other taxa.[3]
The genus is set apart from superficially similar script lichens by the coexistence of partly carbonised lirellae, smooth periphysoids, an inspersion-free hymenium and small, I– muriform spores. In Carbacanthographis the excipulum is completely carbonised; Acanthothecis and Anomomorpha have spiny ( spinulose ) or iodine-positive elements; and Gyphis has significantly larger spores. A diagnostic additional feature in several species, such as G.corticicola, is a rectangular perispore that folds at the poles when mounted in potassium hydroxide.[4]
Ecology
Gymnographopsis is pantropical, ranging from the lowland Amazon basin and West-Central African rainforests to Indochina, New Guinea and north-eastern Australia. All known species are corticolous, occupying shaded trunks and lower branches in evergreen forests; their intolerance of heavy disturbance makes them handy indicators of long-standing, moist woodland.[3]
Work in Mexico's seasonally dry forests uncovered the corticolous G.corticicola, the first Northern-Hemisphere record for the genus and its smallest-spored member (about 12 × 5μm). Molecular data place the taxon within subfamily Redonographoideae and suggest further undiscovered diversity across Mesoamerica.[4]
↑ Lücking, Robert; Hodkinson, Brendan P.; Leavitt, Steven D. (2017). "The 2016 classification of lichenized fungi in the Ascomycota and Basidiomycota–Approaching one thousand genera". The Bryologist. 119 (4): 361–416. doi:10.1639/0007-2745-119.4.361.
1 2 3 Dodge, C.W. (1966). "New lichens from Chile". Nova Hedwigia. 12: 307–352.
1 2 3 Miranda-González, Ricardo; Lücking, Robert; Barcenas-Peña, Alejandrina; Ángeles Herrera-Campos, María de los (2020). "The new genus Jocatoa (Lecanoromycetes: Graphidaceae) and new insights into subfamily Redonographoideae". The Bryologist. 123 (2): 127–143. doi:10.1639/0007-2745-123.2.127.
↑ Follmann, G. (1967). "Die Flechtenflora der nordchilenischen Nebeloase Cerro Moreno" [The lichen flora of the northern Chilean fog oasis Cerro Moreno]. Nova Hedwigia (in German). 14: 213–281.
↑ Egea, J.M.; Torrente, P. (1996). "Tres nuevas especies de hongos liquenizados de la Provincia del Cabo (Sudáfrica)" [The lichen flora of the northern Chilean fog oasis Cerro Moreno]. Cryptogamie Bryologie Lichénologie (in Spanish). 17 (4): 295–312.
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