Cryptothecia is a genus of white to greenish crustose lichens that grow on bark, wood, or leaves, in tropical or subtropical areas worldwide. It has a conspicuous prothallus that develops around its periphery which can be bright red in some species, hence the common name wreath lichen. The main vegetative body (thallus) lacks a cortex (ecorticate and is often immersed in the substrate or byssoid. The medulla is white, well defined, and often peppered with calcium oxalate crystals. Ascomata are not well defined, being cushions of soft white mycelium immersed in the medullary tissue, hence the name from the Greek krypto = "to conceal" and theke = "a container or sheath". It contains Trentepohlia, a green alga, as its photobiont partner.
Enterographa is a genus of lichens in the family Roccellaceae.
Architrypethelium is a genus of lichen-forming fungi in the family Trypetheliaceae.
Astrothelium is a large genus of corticolous (bark-dwelling) lichens in the family Trypetheliaceae. The genus is characterized by a corticate thallus and diverse ascomata structures, which can be simple, aggregated, or forming pseudostromata. Astrothelium is also notable for the carbonized walls of its ascomata, the so-called textura intricata arrangement of cells in these walls, and various forms of distoseptate, transparent spores.
André Aptroot is a Dutch mycologist and lichenologist. His primary research focus is on biodiversity, particularly tropical lichens, encompassing systematics, floristic surveys, and taxonomic reviews. A prolific researcher, he has published more than 500 scientific papers and described hundreds of new fungal and lichen species.
Malmidea is a genus of crustose lichens and the type genus of the family Malmideaceae. It was established in 2011 to contain a phylogenetically distinct group of species formerly placed in the genus Malcolmiella. The crust-like thallus of Malmidea lichens has a surface that varies from smooth to rough, featuring textures such as verrucose (wart-like), granulose (grainy), or pustulate (pimpled). These textures are often formed by goniocysts, which are spherical clusters of green algal cells from the family Chlorococcaceae, encased in fungal hyphae. Malmidea comprises nearly 70 mostly tropical species that grow on bark, although a few grow on leaves.
Coenogonium is a genus of filamentous lichens in the monotypic family Coenogoniaceae. It has about 90 species. Most species are leaf-dwelling or grow on bark, although a few are known to grow on rocks under certain conditions, and some are restricted to growth on termite nests. The genus was circumscribed in 1820 by German naturalist Christian Gottfried Ehrenberg.
Herpothallon is a genus of crustose lichens in the family Arthoniaceae. It has about 50 species.
Crypthonia is a genus of lichen-forming fungi in the family Arthoniaceae. It has 16 species. The genus was circumscribed in 2010 by Andreas Frisch and Göran Thor, with Crypthonia polillensis assigned as the type species.
Myriostigma is a genus of lichens in the family Arthoniaceae. The genus was circumscribed by German lichenologist August von Krempelhuber in 1874.
Acanthothecis latispora is a species of corticolous (bark-dwelling) lichen in the family Graphidaceae. Found in Brazil, it was formally described as a new species in 2022 by Shirley Cunha Feuerstein and André da Silveira. The type specimen was collected by the first author from Turvo State Park. Here the lichen was growing on branches in open areas of the Atlantic Forest. It has a whitish to greenish thallus with a black prothallus. Its asci contain a single ascospore; the spores are densely muriform and measure 82–100 by 27–35 μm. The specific epithet refers to the wide spores. Acanthothecis latispora contains norstictic and stictic acids; these are lichen products that are detectable using thin-layer chromatography.
Acanthothecis megalospora is a species of corticolous (bark-dwelling) lichen in the family Graphidaceae. Found in Brazil, it was formally described as a new species in 2022 by Shirley Cunha Feuerstein and Robert Lücking. The type specimen was collected from a São Paulo farm near Itaguatins (Tocantins); here it was found growing on tree bark in cerrado. The lichen has a whitish grey thallus. Its asci contain a single, more or less rectangular ascospore with 15 to 17 transverse septa. The specific epithet refers to these large spores. Acanthothecis megalospora contains norstictic acid, connorstictic acid, and protocetraric acid, which are lichen products than can be detected using thin-layer chromatography.
Acanthothecis submuriformis is a species of corticolous (bark-dwelling) lichen in the family Graphidaceae. Found in Brazil, it was formally described as a new species in 2022 by André Aptroot, Robert Lücking, and Marcela Eugenia da Silva M.Cáceres. The type specimen was collected from the Parque Natural Municipal ; here the lichen was found growing on tree bark in primary rainforest.
Astrothelium minicecidiogenum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Costa Rica, it was formally described as a new species in 2019 by lichenologists André Aptroot and Harrie Sipman. The type specimen was collected by Aptroot from Tenorio Volcano National Park (Alajuela) at an altitude of 700 m (2,300 ft). The lichen has a smooth and shiny, olive-green thallus with a cortex, but lacking a prothallus. It covers areas up to about 7 cm (3 in) in diameter. It has pear-shaped (pyriform) ascomata, measuring 0.7–1.3 mm in diameter, which occur singly, immersed in the bark and under the thallus cortex. They are surrounded by carbonized (blackened) walls up to 80 μm thick. The ascospores are hyaline to yellowish, and muriform, with dimensions of 70–90 by 20–25 μm. They number eight per ascus. The specific epithet minicecidiogenum refers to both its relatively small spores and its resemblance to Astrothelium cecidiogenum.
Pseudopyrenula miniflavida is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2019 by lichenologists André Aptroot and A.D.Nunes. The type specimen was collected from Mata do IFS at an altitude of 50 m (160 ft). The lichen has a whitish-grey thallus without a cortex. It has hemispherical ascomata that are mostly black but sometimes partly covered with a whitish pruina. The hamathecium contains yellow oil droplets that dissolve but do not change colour in a solution of KOH. The ascospores are hyaline with three septa and measure 15–17 by 5.5–6.5 μm. The specific epithet miniflavida alludes to both its small spores as well as the characteristic yellow oil droplets in the hamathecium.
Architrypethelium hyalinum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Costa Rica and Brazil, it was formally described as a new species in 2008 by lichenologist André Aptroot. The type specimen was collected by Harrie Sipman from the Las Cruces Biological Station in Puntarenas. The lichen has a smooth to uneven, olive-green thallus. Its ascomata occur solitarily, have an apical ostiole, and measure 0.7–1.5 mm in diameter. Ascospores number 4 to 8 per ascus, have an oblong to ellipsoid shape with 3 septa, and measure 100–150 by 30–50 μm. These spores are among the largest of the 3-septate lichens in the Trypetheliaceae. Both the thallus and ascomata contain lichexanthone, a lichen product that causes these structures to glow yellow when lit with a long-wavelength UV light; A. hyalinum is the only species in genus Architrypethelium that contains lichexanthone.
Gyalideopsis aptrootii is a species of corticolous lichen in the family Gomphillaceae. Found in southern Brazil, it was described as a new species in 2018. Defining features of this lichen include the unique crescent-shaped structure of its hyphophores, the single-spored asci, and the relatively small size of the ascospores.
Coniocarpon is a genus of lichen-forming fungi in the family Arthoniaceae. It has eight species of corticolous (bark-dwelling) lichens. This genus is distinct for its crystalline orange, red, and purple quinoid pigments in the ascomata that turn purple in potassium hydroxide solution, its colourless, transversely septate ascospores with large apical cells, and its rounded to lirellate ascomata.
Cryptothecia albomaculatella is a species of corticolous (bark-dwelling), crustose lichen in the family Arthoniaceae. It is a common lichen species in Thailand, and has also been recorded from Assam, India.
