| Polymeridium | |
|---|---|
Scientific classification  | |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Dothideomycetes |
| Order: | Trypetheliales |
| Family: | Trypetheliaceae |
| Genus: | Polymeridium (Müll.Arg.) R.C.Harris (1980) |
| Type species | |
| Polymeridium contendens (Nyl.) R.C.Harris | |
| Synonyms | |
| |
Polymeridium is a genus of lichen-forming fungi in the family Trypetheliaceae. [1] Species in the genus are corticolous (bark-dwelling) and typically occur in tropical areas.
The genus was originally circumscribed as a section of the genus Arthopyrenia by Swiss lichenologist Johannes Müller Argoviensis in 1883. Richard Harris elevated it to generic status in 1980. [2] In his 1993 revision of the genus, Harris identified 19 species. Utilizing a broad species concept, he acknowledged the presence of variations in chemistry and hamathecial inspersion within individual species. [3] André Aptroot and Marcela Cáceres again revised the genus in 2014, using the absence or presence of lichexanthone and the absence or presence of hamathecial inspersion as distinguishing characters for species. The monotypic genus Exiliseptum was incorporated into Polymeridium, as it only differs in one characteristic from several Polymeridium species and does not possess any unique features. As a result of this work, the number of species in the genus increased from 27 to 53. [4]
Polymeridium is characterized by a white to yellowish or grey thallus, which is usually ecorticate (i.e., it lacks a cortex ). Its ascomata , the fruiting bodies of the lichen, are simple or fused, appearing as black, spherical to pyriform structures that emerge from the substratum . The ostiole, or opening of the ascomata, can be apical to lateral, brown to black, or exhibit a red anthraquinone colour. [4]
The hamathecium , which refers to the filamentous tissue within the ascomata, is colourless and may contain hyaline or red oil droplets that turn green when treated with potassium hydroxide (KOH) solution. Ascospores are the reproductive spores of the lichen and typically occur in groups of 4 to 8 per ascus. They are colourless, ellipsoid to fusiform in shape, with rounded to subacute ends, and symmetrically 3 to 13- septate to muriform . The ascospores are not constricted at the septa and are sometimes surrounded by a thin to 2–5 μm-thick gelatinous sheath. The septa within the ascospores are not thickened, and the lumina are rectangular and slightly rounded, but not diamond-shaped. [4]
Conidiomata , or structures that produce conidia (asexual spores), are rather rare in the genus Polymeridium. In terms of secondary chemistry, the thallus occasionally contains lichexanthone, while anthraquinones are rarely present in the ostiole or hamathecium. [4]
Porina is a genus of lichens in the family Trichotheliaceae. A 2020 estimate places about 145 species in the widespread genus.
Anisomeridium is a genus of lichens in the family Monoblastiaceae. The type species was originally named Arthopyrenia xylogena by Swiss botanist Johannes Müller Argoviensis in 1883; in 1928, Maurice Choisy defined the genus Anisomeridium, designating A. xylogena the type species.
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.
Trypethelium is a genus of lichenized fungi in the family Trypetheliaceae. The widespread genus contains about 50 species that are predominantly found in tropical areas. Trypethelium was circumscribed by German botanist Kurt Polycarp Joachim Sprengel in 1804.
Astrothelium sipmanii is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in Guyana.
Astrothelium inspersogalbineum is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Singapore, it was formally described as a new species in 2016 by lichenologists André Aptroot and Gothamie Weerakoon. The type specimen was collected by the second author in a rainforest, where it was found growing on smooth bark. The lichen has a smooth and somewhat shiny, pale greenish-grey thallus with a cortex and a thin black prothallus line. It covers areas of up to 3 cm (1.2 in) in diameter, and does not induce gall formation in its host plant. A yellow to orange anthraquinone was the only lichen product detected in the collected specimens using thin-layer chromatography. A. inspersogalbineum also contains the compound lichexanthone, which causes the thallus to fluoresce yellow when lit with a long-wavelength UV light. The main characteristics of the lichen distinguishing it from others in Astrothelium are its inspersedhamathecium; its ascospores, with dimensions of 20–25 by 9–11 μm; and the grouping of its ascomata, which can fuse together to become irregularly confluent.
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 curvisporum 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 Parque Natural Municipal de Porto Velho, in a primary rainforest. The lichen has a smooth and somewhat shiny, olive-green to olive-brown thallus that lacks a prothallus and covers areas of up to 5 cm (2 in) in diameter. The presence of the lichen does not induce the formation of galls in the host. The ascomata are more or less spherical (globose), measuring 0.8–1.2 mm in diameter, and typically occur in groups of 3 to 15, usually immersed in pseudostromata. The species epithet curvisporum refers to the curved ascospores, which have five septa that divide the spore into distinct compartments. The spores have a thick gelatinous layer that is 17–22 μm thick. No lichen products were detected in collected samples of the species using thin-layer chromatography. The characteristics that distinguish A. curvisporum from other members of Astrothelium include its grouped ascomata and its curved ascospores.
Astrothelium disjunctum 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 Parque Natural Municipal de Porto Velho, in a low-altitude rainforest. The lichen has a smooth and somewhat shiny, pale yellowish-grey thallus that has a black prothallus line and covers areas of up to 5 cm (2 in) in diameter. The ascomata are roughly spherical (globose) and typically occur in groups of 5 to 25, usually immersed in the bark tissue as pseudostromata. The characteristic that largely distinguishes it from other members of Astrothelium are its smooth to coarsely uneven thallus. Astrothelium disjunctum is somewhat similar to A. bicolor, but that species has smaller ascospores.
Astrothelium duplicatum 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 Parque Natural Municipal de Porto Velho, where it was found growing on the smooth bark of a tree in a park near a rainforest, and on tree twigs in the forest. The lichen has a smooth and somewhat shiny, olive-green thallus surrounded by a black prothallus and covers areas of up to 5 cm (2 in) in diameter. The presence of the lichen does not induce the formation of galls in its host. The ascomata are roughly spherical and typically aggregate in groups of about five to fifty, usually immersed in the bark tissue as pseudostromata. Its ascospores are hyaline, spindle-shaped and measure 45–55 by 11–15 μm. The use of thin-layer chromatography on collected lichen samples revealed the presence of an anthraquinone compound, possibly parietin. The characteristics that distinguish Astrothelium duplicatum from other members of Astrothelium include the internal, yellow pigment of its ascomata; and the dimensions of its ascospores, which are about 3–4 times as long as they are broad. Astrothelium mesoduplex is similar in appearance, but that species lacks yellow to orange pseudostromata and has shorter 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 flavomurisporum 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 from the Estação Ecológica de Cuniã, in a low-altitude primary rainforest. The lichen has a smooth and somewhat shiny, olive-green thallus that lacks a prothallus and covers areas of up to 7 cm (2.8 in) in diameter. The ascomata are pear-shaped (pyriform), measuring 0.5–0.7 mm in diameter, and typically aggregate in groups of two to five, usually quite immersed in the bark tissue. Ascospores are hyaline, ellipsoid, and muriform ; they measure 165–200 by 28–35 μm and have a thickened central septum. The presence of the lichen does not induce the formation of galls in the host. Thin-layer chromatography did not reveal the presence of any lichen products in the collected lichen samples. The characteristics that distinguish Astrothelium flavomurisporum from other members of Astrothelium include the dispersed groups of fused, immersed ascomata; and the median thickening of the ascospores.
Dictyomeridium is a genus of corticolous (bark-dwelling), crustose lichens in the family Trypetheliaceae. It has eight species.
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 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 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.
Astrothelium mesoduplex is a species of lichen in the family Trypetheliaceae. It is similar to A. flavoduplex but has larger ascospores and lacks lichexanthone. This lichen species has been found only in Brazil, particularly in primary forests.
Astrothelium testudineum is a species of corticolous (bark-dwelling) lichen in the family Trypetheliaceae. It is found in Brazil.