| Placopyrenium | |
|---|---|
 | |
| Placopyrenium bucekii | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Eurotiomycetes |
| Order: | Verrucariales |
| Family: | Verrucariaceae |
| Genus: | Placopyrenium Breuss (1987) |
| Type species | |
| Placopyrenium bucekii (Nádv. & Servít) Breuss (1987) | |
Placopyrenium is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. [1]
The genus was circumscribed in 1987 by the Austrian lichenologist Othmar Breuss. He assigned Placopyrenium bucekii as the type species. [2]
The genus Placopyrenium is characterised by its epilithic (growing on rocks) thallus, which is thick and distinctly patterned, breaking into areoles (small, island-like sections) or squarrose-areolate (with scale-like, spreading areoles). These areoles have a unique shape, being noticeably narrowed at their base and extending into elongated stipes (stalks), which are ashen in colour on the upper surface due to a protective epinecral layer , while the underside is black. The thallus lacks rhizohyphae (root-like hyphae) and the stipes are directly attached to the substrate . [2]
The entire thallus is composed of cells that are either angular or rounded, measuring 5–10 μm in diameter, forming a structure that is nearly paraplectenchymatous , meaning the cells are closely packed together. The areolae's base and sides are enveloped in a carbonaceous (blackened) cortical layer, providing durability and protection. [2]
In terms of reproductive structures, Placopyrenium develops perithecia (fruiting bodies) within the thallus. These perithecia lack an involucrellum (an outer layer or envelope). The asci (spore-producing structures) within the perithecia are clavate , meaning they are shaped like a club. The spores produced in these asci are arranged in two rows ( biseriate ), and are either ellipsoidal or ovoid-oblong in shape. These spores are colourless and typically simple , although they are often uniseptate, meaning they have a single internal division (septum). Additionally, the genus produces short, rod-shaped conidia (asexual spores). [2]
Verrucariaceae is a family of lichens and a few non-lichenised fungi in the order Verrucariales. The lichens have a wide variety of thallus forms, from crustose (crust-like) to foliose (bushy) and squamulose (scaly). Most of them grow on land, some in freshwater and a few in the sea. Many are free-living but there are some species that are parasites on other lichens, while one marine species always lives together with a leafy green alga.
Clavascidium is a genus of lichens in the family Verrucariaceae. The genus was circumscribed in 1996 by Austrian lichenologist Othmar Breuss. Because the type species of the genus, Clavascidium umbrinum, has been shown using molecular phylogenetics to belong to genus Placidium, Cécile Gueidan and colleagues proposed to unite Clavascidium with Placidium in a 2009 publication. Despite this, the genus has been retained in recent publications of fungal classification.
Bagliettoa is a genus of lichen-forming fungi in the family Verrucariaceae. The genus was circumscribed by Italian lichenologist Abramo Bartolommeo Massalongo in 1853. Bagliettoa species are endolithic, growing between the grains of solid rock.
Agonimia is a genus of lichen-forming fungi in the family Verrucariaceae.
Placidium is a genus of crustose to squamulose to almost foliose lichens. The genus is in the family Verrucariaceae. Most members grow on soil, but some grow on rock (saxicolous). The fruiting bodies are perithecia, flask-like structures immersed in the lichen body (thallus) with only the top opening visible, dotting the thallus. Lichen spot tests are all negative. Members of the genus lack rhizines, but otherwise resemble members of the genus Clavascidium.
Placidiopsis is a genus of lichens in the family Verrucariaceae. The genus was circumscribed by Italian naturalist Francesco Beltramini de Casati in 1858, with Placidiopsis grappae assigned as the type species.
Heteroplacidium is a genus of lichen-forming fungi in the family Verrucariaceae. The genus was circumscribed by Austrian lichenologist Othmar Breuss in 1996 with Heteroplacidium imbricatum assigned as the type species. It was proposed as a segregate of Catapyrenium. Other morphologically similar genera are Neocatapyrenium, Placidium, and Scleropyrenium, although molecular phylogenetic analyses indicate that they are independent monophyletic lineages within the Verrucariaceae.
Hydropunctaria is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. The genus includes both aquatic and amphibious species, with members that colonise either marine or freshwater habitats. The type species, Hydropunctaria maura, was formerly classified in the large genus Verrucaria. It is a widely distributed species common to littoral zones. Including the type species, five Hydropunctaria lichens are considered marine species: H. adriatica, H. amphibia, H. aractina, H. orae, and H. oceanica.
Parabagliettoa is a genus of crustose lichens in the family Verrucariaceae. It has 3 species. The genus was circumscribed in 2009 by Cécile Gueidan and Claude Roux, with Parabagliettoa dufourii assigned as the type species.
Heteroplacidium zamenhofianum is a species of lichenicolous (lichen-eating) lichen in the family Verrucariaceae. As a juvenile, it is parasitic on some members of the lichen genus Staurothele, but later becomes independent and develops a brown, crustose thallus. Characteristic features of the lichen include its dark brown, somewhat squamulous thallus and relatively small ascospores. It is widely distributed in Europe and North America.
Phylloblastia is a genus of foliicolous (leaf-dwelling) lichens in the family Verrucariaceae. The genus was circumscribed in 1921 by Finnish lichenologist Edvard August Vainio, with Phylloblastia dolichospora assigned as the type species.
Willeya is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. It has 12 species. Most species are found in southeast Asia, although individual representatives are known from Australia, Europe, and North America.
Wahlenbergiella is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. It has three species, all of which live in marine intertidal zones where they get periodically immersed in seawater. Wahlenbergiella closely resembles another lichen genus that includes marine species, Hydropunctaria. Wahlenbergiella was circumscribed in 2009 by Cécile Gueidan and Holger Thüs. They initially included two species: W. striatula, and the type, W. mucosa. The generic name honours Swedish naturalist Göran Wahlenberg, who originally described both of these species.
Sporodictyon is a genus of crustose lichens in the family Verrucariaceae. It has 10 species. Most species grow on rocks, although some have been recorded overgrowing soil and mosses.
Hydropunctaria rheitrophila is a species of freshwater, saxicolous (rock-dwelling), crustose lichen in the family Verrucariaceae. It was formally described as a new species in 1922 by German lichenologist Georg Hermann Zschacke as a species of Verrucaria. Christine Keller, Cécile Gueidan, and Holger Thüs transferred it to the newly circumscribed genus Hydropunctaria in 2009. It is one of several aquatic lichens that are in this genus. The photobiont partner of Hydropunctaria rheitrophila is a yellow-green alga.
Trimmatothele is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. It has five species. The genus was formally published by lichenologist Alexander Zahlbruckner in 1903. The type species, Trimmatothele perquisita, was originally collected from Norway by Johannes M. Norman, who placed it in the genus Coniothele in 1868. Diagnostic characteristics of Trimmatothele include a thin thallus with a smooth surface; small perithecia that are partially immersed in the substrata and have an involucrellum; asci that contain multiple ascospores; and small, simple ascospores. Trimmatothele has been described as one of the most poorly known genera of lichens due to the rarity of its species, the few available herbarium specimens, and some missing type specimens.
Wahlenbergiella tavaresiae is a species of saxicolous (rock-dwelling), crustose lichen in the family Verrucariaceae. Known from several locations in the San Francisco Bay area of the United States, it is a marine lichen that inhabits intertidal zones, and as such is immersed in seawater on a regular basis. Associated algal species include the red algae Hildenbrandia and Mastocarpus papillatus, and the brown algae Pelvetiopsis and Fucus. Petroderma maculiforme, a brown alga, is the photobiont partner in the lichen.
Verrucaria viridula is a common and widely distributed species of saxicolous (rock-dwelling), crustose lichen in the family Verrucariaceae. Although it is a somewhat morphologically variable species, two persistent distinguishing characteristics are its relatively large perithecia, which are often curved into a beak, and its large ascospores.
Hydropunctaria amphibia is a species of saxicolous (rock-dwelling), crustose lichen in the family Verrucariaceae. One of several marine lichens in the genus Hydropunctaria, is widely distributed across Europe, extending from Norway to the Mediterranean and the Iberian coasts, and has a nearly ubiquitous presence along the Catalan coast of Spain. In North America, it is found along the Atlantic Coast from Nova Scotia to the Boston Harbor islands, where its presence in low-pollution areas indicates its potential as a bioindicator for marine lichen community health, and on the west coast in British Columbia, particularly in the Gwaii Haanas's upper littoral fringe. The black, crust-like thallus grows on seashore rocks – both siliceous rocks and limestone – in the lower supralittoral zone, an area also known as the splash zone. Originally described more than two centuries ago as a species of Verrucaria, Hydropunctaria amphibia sets itself apart from other species in Hydropunctaria through the distinct shape of the perithecium apex, which is either flat-topped or scalloped, in contrast to the typically rounded or immersed apex seen in its relatives.