Matthew Paul Nelsen

The Strigulales are an order of lichen-forming fungi in the class Dothideomycetes. It contains two families: Strigulaceae and Tenuitholiascaceae, with a combined total of 115 species. The order was proposed in 2013. Most species in the order are foliicolous, that is, they grow on plant leaves.

Viridothelium is a genus of lichen-forming fungi in the family Trypetheliaceae. It comprises 11 species. Viridothelium species can be recognised as a warty, greenish crust whose spore-bearing bumps are more or less the same colour as the rest of the lichen, open by tiny pores, and produce clear multi-celled spores with only modest internal thickening.

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Viridothelium tricolor is a species of lichen-forming fungus in the family Trypetheliaceae. The lichen forms a reddish-brown to yellowish-brown crust on tree bark with a smooth to uneven surface texture. Its reproductive structures are grouped together in irregular to elongated white clusters that stand out conspicuously against the darker lichen body, with the black flask-shaped fruiting bodies embedded within and visible as blackish spots. The species is known from lower-elevation mountain forests and cloud forests in Panama and Venezuela, where it grows on bark of sun-exposed roadside

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Dictyomeridium is a genus of corticolous (bark-dwelling), crustose lichens in the family Trypetheliaceae. It has nine species.

Constrictolumina cinchonae is a species of corticolous (bark-dwelling) crustose lichen in the family Trypetheliaceae. This widespread tropical lichen forms thin, whitish crusts on tree bark and produces small, hemispherical fruiting bodies that are often surrounded by distinctive grey rings. It has a pantropical distribution, being found across warm, humid regions of the Americas, Africa, and Asia, making it one of the most widely distributed members of its genus. The species was originally discovered growing on cinchona bark, which is reflected in its scientific name.

Constrictolumina is a genus of lichen-forming fungi in the family Trypetheliaceae. These tropical lichens form crusty growths that lack a protective outer layer and merge directly with their growing surface. They produce cone-shaped fruiting bodies that push up through the crust and release spores through a tiny opening at the tip. The genus gets its name from the distinctive spores, which have internal walls that fold inward and create narrowed, constricted spaces inside each spore.

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Nigrovothelium is a genus of lichen-forming fungi in the family Trypetheliaceae. It comprises three species. These lichens form crusty patches with a protective outer layer and are easily recognised by their small, black, egg-shaped fruiting bodies that sit directly on the surface. The spores inside have a distinctive diamond-shaped internal cavities that helps distinguish this genus from similar lichens.

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Constrictolumina porospora is a species of lichen in the family Trypetheliaceae. This Caribbean lichen forms thin, whitish crusts on surfaces and produces relatively large, hemispherical fruiting bodies that emerge above the thallus surface. It is distinguished by its unusually large ascospores with granular ornamentation and thick outer layers, and is known only from Dominica where it was originally collected in 1892.

Constrictolumina planorbis is a species of corticolous (bark-dwelling) crustose lichen in the family Trypetheliaceae. This pantropical lichen forms thin, whitish crusts on tree bark and is distinguished by its fruiting bodies that develop broad, shield-like extensions around their openings, giving them a distinctive flattened appearance. It has a wide distribution across tropical regions, being found in North America, the Caribbean, and the Pacific, where it grows in warm, humid environments.

Constrictolumina leucostoma is a species of corticolous (bark-dwelling) crustose lichen in the family Trypetheliaceae. This neotropical lichen forms thin, whitish crusts on tree bark and is distinguished by its small fruiting bodies that are often surrounded by conspicuous thin black rings that frequently merge to form clusters. It has a distribution spanning the Caribbean (including the Antilles), and the United States.

Constrictolumina esenbeckiana is a species of corticolous (bark-dwelling) crustose lichen in the family Trypetheliaceae. This neotropical lichen forms thin, whitish crusts on tree bark and produces small, hemispherical fruiting bodies that often occur in dense clusters of 5–20 individuals that may fuse together sideways. It is known from the Caribbean Antilles and Brazil, where it grows in tropical habitats, though most records are historical.

Bathelium porinosporum is a species of crustose lichen-forming fungus in the family Trypetheliaceae. The lichen forms a light olive-coloured crust on tree bark with a smooth to uneven surface. Its reproductive structures are solitary, dark reddish-brown, somewhat flattened fruiting bodies that sit directly on the lichen surface without being covered by tissue, and are unusual in the genus for producing spores with horizontal divisions rather than complex internal compartments. The species is known from Vietnam, China, and India, where it grows in tropical and subtropical forest regions.

Astrothelium subinterjectum is a species of lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green crust on tree bark with an uneven surface texture. Its reproductive structures are grouped together in rounded to irregular clusters that are covered by greenish tissue and share common openings surrounded by whitish zones. These clusters fluoresce yellow to orange-yellow under ultraviolet light while the surrounding lichen body does not. The species is found in gallery forests within Cerrado landscapes of Brazil, where it has been recorded from São Paulo, Acre, and

Astrothelium subendochryseum is a species of crustose lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green crust on tree bark with a distinctively blistered to strongly uneven surface. Its reproductive structures are grouped together in irregular clusters that are partially covered by greenish tissue on the sides while exposing dark gray-brown tops with small black dots. The species occurs in Atlantic Forest regions of Brazil and has also been recorded from Central America, including El Salvador and Costa Rica.

Astrothelium sordithecium is a species of lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green to gray-green crusty patch on tree bark with a smooth to uneven surface. Its reproductive structures are grouped together in well-defined rounded clusters covered by a whitish layer, and these clusters fluoresce yellow under ultraviolet light while the surrounding lichen body does not. The species is known only from Atlantic Forest in southeastern Brazil, where it grows on bark in disturbed remnants of gallery forest along streams.

Astrothelium obtectum is a species of lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green crust on tree bark with a coarsely folded surface texture. Its reproductive structures are grouped together in rounded to irregular clusters that are covered by greenish tissue and share a common central opening, and the clusters fluoresce orange-yellow under ultraviolet light. The species is known from Atlantic Forest in southeastern Brazil, where it grows along forest trails near streams.

Astrothelium norisianum is a species of crustose lichen-forming fungus in the family Trypetheliaceae. The lichen forms a pale olive-yellow crusty patch on tree bark with a coarsely bumpy, gall-like surface. Its reproductive structures are grouped together in irregular to elongated clusters that are typically covered by a whitish surface layer and fluoresce yellow under ultraviolet light. The species occurs in humid forests from Mexico through Central America to the Amazon basin and Peru.

Astrothelium nicaraguense is a species of lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green crust on tree bark with an uneven to somewhat blistered surface texture. Its reproductive structures are either solitary or loosely grouped, appearing as raised bumps covered in greenish tissue with black dots at the top, and each spore sac produces a single large ascospore divided into many small compartments. The species occurs in montane rainforests of Central America and has also been recorded from the Amazon region of Brazil.

Astrothelium megacrypticum is a species of crustose lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green crusty patch on tree bark with a distinctively bumpy, gall-like surface. Its reproductive structures are completely hidden within the lichen body and are unusual in that each spore sac contains only a single, exceptionally large ascospore rather than the typical eight spores. The species is known only from lower mountain rainforest in Panama, where it grows on roadside trees.

Astrothelium macrostomoides 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 Robert Lücking, Matthew Nelsen, Michel Navarro Benatti. The type specimen was collected by the first author from the Santuário do Caraça (Reserva Particular do Patrimônio Natural, Minas Gerais) at an altitude between 1,300 to 1,400 m (4,300 to 4,600 ft); there, in the Atlantic Forest biome, it was found growing on bark in a gallery forest along a river. The lichen has an uneven to coarsely bullate,

Astrothelium leucosessile is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Panama, it was formally described as a new species in 2016 by Robert Lücking, Matthew Nelsen, and André Aptroot. The type specimen was collected by the first author from the Altos de Campana National Park (near Capira) at an altitude between 500 and 600 m (1,600 and 2,000 ft); there, in a submontane forest, it was found growing on the bark of roadside trees. The lichen has a smooth to uneven, light olive-grey thallus that covers areas of up to 5 cm (2 in), and has

Astrothelium laevithallinum 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 Robert Lücking, Matthew Nelsen, and Marcelo Marcelli. The type specimen was collected by the first author from the Santuário do Caraça (Reserva Particular do Patrimônio Natural, Minas Gerais) at an altitude between 1,300 and 1,400 m (4,300 and 4,600 ft); there, in Atlantic Forest, it was found in a forest remnant near a waterfall. The lichen has a smooth to uneven, green thallus that covers areas of up to

Astrothelium cryptolucens is a species of corticolous (bark-dwelling), crustose lichen in the family Trypetheliaceae. Found in Panama, it was formally described as a new species in 2016 by Robert Lücking, Matthew Nelsen, and Noris Salazar Allen. The type specimen was collected by the first author from the Altos de Campana National Park (near Capira) at an altitude of 500–600 m (1,600–2,000 ft); there, in a submontane rainforest, it was found growing on the bark of roadside trees. The lichen has an uneven to coarsely bumpy, olive-yellow thallus that covers areas of up to 10 cm (4 in) in

Astrothelium carassense 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 Robert Lücking, Matthew Nelsen, and Marcelo Marcelli. The type specimen was collected by the first author from the Santuário do Caraça (Reserva Particular do Patrimônio Natural, Minas Gerais), at an altitude between 1,300 and 1,400 m (4,300 and 4,600 ft). The lichen has an uneven to bumpy, pale olive-yellow thallus that covers areas of up to 10 cm (4 in) in diameter. The pseudostromata are covered with an

Architrypethelium lauropaluanum is a species of crustose lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-yellow, crusty patch on tree bark with a distinctively bumpy, wart-like surface. Its reproductive structures are flask-shaped bodies deeply embedded between the raised bumps, and it produces unusually large ascospores that typically have three divisions. The species is found in montane Atlantic rainforest regions of Brazil and has also been recorded from lowland rainforest in Peru.

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