Astrothelium diaphanocorticatum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Papua New Guinea, it was formally described as a new species in 2019 by lichenologists André Aptroot and Harrie Sipman. The type specimen was collected by Sipman on Mount Wilhelm at an altitude of 2,900 m (9,500 ft). The lichen has an olive-green to yellowish-green thallus that is strongly convex and swollen (bullate) and partially comprises small, roughly spherical globules. The thallus has a thick, clear cortex in which the algal cells can be visualised as green dots. It has roughly spherical ascomata, measuring 0.7–1.3 mm in diameter, which appear singly on the thallus surface, or, in some instances, fused together laterally. The ascospores are hyaline, ellipsoid in shape with three transverse septa, and measure 25–28 by 10–12 μm. The specific epithet diaphanocorticatum alludes to the transparent cortex.
Astrothelium stromatofluorescens is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is only known to occur in a few locations in Brazil and Bolivia.
Astrothelium sexloculatum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Guyana and Papua New Guinea, it was formally described as a new species in 2016 by Dutch lichenologist André Aptroot. The type specimen was collected by Harrie Sipman on the Dadadanawa ranch at an altitude of 120 m (390 ft); there, it was found growing on smooth tree bark in a savanna. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus with a cortex and a thin black prothallus line. It covers areas of up to 9 cm (3.5 in) in diameter. Both the thallus and the pseudostromata contain lichexanthone, a lichen product that causes these structures to fluoresce yellow when lit with a long-wavelength UV light. The combination of characteristics of the lichen that distinguish it from others in Astrothelium are the indistinctly pseudostromatic ascomata, with erumpent to prominent pseudostromata that are covered by thallus. The species epithet sexloculatum refers to the ascospores, which are divided into six chambers (locules) by five transverse septa.
Polymeridium rhodopruinosum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Puerto Rico, it was formally described as a new species in 2016 by Dutch lichenologist André Aptroot. The type specimen was collected by the author from Vereda Los Viveros in the Maricao State Forest (Maricao) at an altitude of 850 m (2,790 ft); there, it was found in a sclerophyllous forest growing on tree bark. The lichen has a white thallus lacking a cortex. The only lichen product detected from collected specimens using thin-layer chromatography was an anthraquinone compound. The combination of characteristics of the lichen that distinguish it from others in Polymeridium are the ascomata with external, red pruina that turn dark blood red with a K+ spot test; and the dimensions of its ascospores.
Astrothelium eumultiseptatum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by lichenologists André Aptroot and Marcela Cáceres. The type specimen was collected by the authors in the Fazenda São Francisco, in a low-altitude primary rainforest. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus with a black prothallus line and covers areas of up to 7 cm (2.8 in) in diameter. The ascomata are pear-shaped (pyriform) and typically aggregate in groups of two to five, usually immersed in the bark tissue as pseudostromata. The ostioles of the ascomata contains lichexanthone, a lichen product that causes these structures to glow yellow when lit with a long-wavelength UV light. The main characteristic that distinguishes it from other members of Astrothelium are its ascospores, which measure 65–70 by 15–17 μm, and only have transverse septa.
Astrothelium sinuosum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2016 by André Aptroot and Emerson Gumboski. The type specimen was collected by the second author from the Rio Pardinho e Rio Vermelho Environmental Protection Area ; there, in an Atlantic Forest habitat, it was found growing on smooth tree bark.
Polymeridium xanthoexcentricum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. It is found in southwestern Bolivia.
Polymeridium albidoreagens is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Brazil, it was formally described as a new species in 2013 by lichenologists André Aptroot, Aline Anjos Menezes, and Marcela Cáceres. The type specimen was collected in Rondônia's Porto Velho, Parque Natural Municipal, at an altitude of 100 m (330 ft); other specimens have been reported from Ceará in the Chapada do Araripe. This lichen species is similar to Polymeridium albidum but is characterized by its UV+ (yellow) thallus. The ecorticate, whitish-grey thallus features spherical, erumpent, solitary ascomata with diameters ranging from 0.2 to 0.4 mm and an apical ostiole. The hamathecium is not inspersed, and the ascospores number 8 per ascus, contain 3 septa, and measure 20–23 by 6–8 μm without ornamentation. The lichen's chemistry includes the presence of lichexanthone.
Polymeridium albidovarians is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. The lichen was first discovered in Indonesia on the island of Java, specifically at the Kawi-complex, Tjemarakandang, at an altitude of 2,700 m (8,900 ft). This species closely resembles Polymeridium albidum, but is differentiated by its UV+ (yellow) thallus and inspersedhamathecium. The yellowish-white, ecorticate thallus features spherical, erumpent, solitary ascomata measuring 0.2–0.4 mm in diameter, with an apical ostiole. The hamathecium is inspersed with oil droplets, and the ascospores number eight per ascus, contain three septa, and measure 20–23 by 6–8 μm without ornamentation. The lichen's chemistry is characterized by the presence of lichexanthone.
Polymeridium alboflavescens is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. First described from specimens collected in Venezuela, it closely resembles Polymeridium albocinereum but exhibits a UV+ (yellow) thallus. The ecorticate, whitish-grey thallus is characterized by spherical, erumpent, solitary ascomata measuring 0.3–0.5 mm in diameter, with an apical ostiole. The hamathecium is not inspersed, and the ascospores number 8 per ascus, contain 7 to 11 septa, and measure 28–39 by 6–9 μm without ornamentation. The lichen's chemistry features lichexanthone. In addition to the Venezuelan holotype, Polymeridium alboflavescens has been reported in Brazil, particularly in the Ceará region at the Chapada do Araripe, where several specimens were collected in 2012.
Polymeridium costaricense is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Costa Rica and Brazil, it was formally described as a new species in 2013 by Dutch lichenologist André Aptroot. The lichen bears a resemblance to Polymeridium chioneum but is differentiated by its non-fluorescent thallus under ultraviolet light (UV−). The type specimen of P. costaricense was collected in Palo Verde National Park, Guanacaste, Costa Rica, along the trail to Rio Tempisque, growing on tree bark. The type specimen of P. costaricense was initially reported and illustrated as P. chioneum by Aptroot and colleagues in 2008. Additional specimens have been examined from Chapada do Araraipe, Ceará, Brazil.
Polymeridium inspersum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in pantropical regions, it was formally described as a new species in 2013 by Dutch lichenologist André Aptroot. This lichen closely resembles Polymeridium subcinereum but is differentiated by its inspersedhamathecium. The type specimen of P. inspersum was collected by the author in Kuranda, Queensland, along the Jumrum Creek track, growing on a twig.
Polymeridium multiforme is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in the Neotropics, with specimens recorded from Brazil, Guyana, and Venezuela. The lichen was described by Dutch lichenologist André Aptroot in 2013. This lichen closely resembles Polymeridium quinqueseptatum, but its thallus is whitish-grey and fluoresces yellow under ultraviolet light. Additionally, the hamathecium of P. multiforme is not interspersed with oil droplets. The type specimen was collected in Guyana, at the base of Makarapan Mountain, on the bark of a Myrsinaceae tree.
Polymeridium multiseptatum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Brazil, it was described by lichenologists André Aptroot, Aline Anjos Menezes, and Marcela Cáceres in 2013. The thallus of P. multiseptatum is ecorticate and whitish-grey in color, with the distinctive feature of fluorescing yellow under ultraviolet light. This lichen closely resembles Polymeridium quinqueseptatum, with the primary distinguishing characteristic being the UV+ (yellow) thallus. The ascomata are 0.2–0.4 mm in diameter, featuring a solitary, spherical centrum that is erumpent. The ostiole is apical, and the hamathecium is interspersed with oil droplets, with filaments profusely anastomosing. There are eight ascospores per ascus, which are iodine-negative, 4–7-septate, and measure 18–28 by 5–7 μm. The ascospores are not ornamented, and the wall is not thickened. The lichen's chemistry reveals the presence of lichexanthone. The type specimens were collected in Chapada do Araripe, Ceará, at an altitude of 800 m (2,600 ft), where it was found growing on tree bark.
Polymeridium neuwirthii is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Venezuela, it was formally described as a new species in 2014 by Dutch lichenologist André Aptroot. This ecorticate lichen has a pinkish-grey thallus that does not fluoresce under ultraviolet light. P. neuwirthii is similar to Polymeridium quinqueseptatum but can be differentiated by its hamatheciuminspersed with large oil droplets and consistently 7-septate, rough ascospores. The ascomata are 0.4–0.6 mm in diameter, with a spherical centrum that is erumpent and solitary. The ostiole is apical, and the hamathecium contains large oil droplets. There are eight ascospores per ascus, which are iodine-negative, 7-septate, and measure 30–33 by 9–10 μm. The ascospore wall is roughly ornamented. No chemical substances have been detected in this lichen. The type specimen was collected in Puerto Ayacucho, Venezuela, on a twig of a shrub. The species is named in honour of the collector of the type and only specimen, Gerhard Neuwirth.
Polymeridium submuriforme is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It occurs in the Philippines. This ecorticate lichen is characterized by its pinkish-grey thallus, which does not fluoresce under ultraviolet light. P. submuriforme is similar to Polymeridium cinereonigricans but can be distinguished by its much smaller ascospores and inspersedhamathecium. The ascomata measure 0.3–0.6 mm in diameter, with a solitary, spherical centrum that is erumpent. As the ascomata age, the wall expands up to 0.2 mm sideways. The ostiole is apical, and the hamathecium is inspersed. The ascospores number 6–8 per ascus, iodine-negative, somewhat muriform, and measure 18–20 by 6–7.5 μm. These ascospores are not ornamented and are surrounded by a 1–2 μm wide gelatinous sheath. No chemical substances have been detected in this lichen. The type specimen was collected from Leyte on tree bark.
Polymeridium tribulationis is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. Found in Australia, it was formally described as a new species in 2013 by Dutch lichenologist André Aptroot. This ecorticate lichen is characterized by its yellowish-white thallus, which does not fluoresce under ultraviolet light. P. tribulationis closely resembles Polymeridium sulphurescens, but can be distinguished by its hamathecium, which is inspersed with oil droplets. The ascomata, measuring 0.4–0.6 mm in diameter, have a spherical centrum that is mostly covered by the thallus. The ostiole is apical and usually surrounded by a ring. The ascospores number eight per ascus, are iodine-negative, have three septa, and measure 20–24 by 7–10 μm without ornamentation. No chemical substances have been detected in the lichen. The type specimen was collected by Mason Hale from Cape Tribulation, Queensland, on tree bark.
Astrothelium supraclandestinum is a species of lichen in the family Trypetheliaceae. This lichen species is closely related to Astrothelium subclandestinum, but differs in its hamathecium, which is not inspersed. The species is widespread and has been observed in several countries across different continents.
Astrothelium aeneum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. It is widely distributed in tropical regions. The lichen's thallus is typically light olive-green to yellowish, often covered in orange pigment, and varies in texture from smooth to uneven. It fluoresces red under ultraviolet light.
Polymeridium endoflavens is a species of lichen in the family Trypetheliaceae, first described in 2016. This species is found in Brazil.
