Leptogium | |
---|---|
Leptogium phyllocarpum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Fungi |
Division: | Ascomycota |
Class: | Lecanoromycetes |
Order: | Peltigerales |
Family: | Collemataceae |
Genus: | Leptogium (Ach.) Gray (1821) |
Type species | |
Leptogium lacerum (Sw.) Gray (1821) |
Leptogium is a genus of lichen-forming fungi in the family Collemataceae. [1] It has about 110 species. [2] Species formerly classified under Leptogium have since been divided among the genera Leptogium, Pseudoleptogium , and Scytinium . Leptogium lichens are predominantly found on tree bark or soil, often among mosses, and sometimes on rocks in moist environments. [3]
In 2013, a proposal supported by molecular phylogenetics data was made to conserve the genus Leptogium with a conserved type, aiming to maintain the current broader classification including both small- squamulose and larger foliose species within Leptogium, while segregating the smaller squamulose species into Scytinium . [4] This conservation was recommended by a vote of 14-0-1 to prevent the necessity of reclassifying about 100 species into new genera such as 'Mallotium. The proposal was widely supported by the Nomenclature Committee for Fungi as it simplifies the taxonomy and maintains historical continuity for the genus Leptogium. [5]
Leptogium is characterized by its foliose, gelatinous thallus, which varies in colour from blue-grey to olive-brown or blackish. The upper and lower cortex of these lichens consists of a single layer of roughly equal-sized cells. The medulla, on the other hand, is made up of loosely intertwined hyphae intermingled with chains of photobiont cells. The upper surface of the thallus can range from smooth to wrinkled or ridged, often exhibiting a glossy appearance, while the lower surface may be smooth, web-like, or hairy, sometimes featuring small clusters of white rhizines. [3]
Leptogium species often possess isidia and have Nostoc as their photobiont. The ascomata are apothecia , which can be sessile or shortly stalked and are predominantly laminal . The thalline margin may persist or become excluded, occasionally displaying a lobulate form. The true exciple is raised, cup-shaped, and mainly composed of periclinally arranged hyphae, with a colour that varies from colourless to reddish-brown. The disc of the lichen is either concave or flat. [3]
The epithecium is colourless to reddish-brown and does not react with solutions of either potassium hydroxide or ammonia. The hymenium is colourless and turns blue when exposed to iodine. The hypothecium is shallow and either colourless or pale yellowish. The hamathecium consists of numerous, conglutinate paraphyses with slightly swollen apices. The asci are club-shaped (clavate) and contain four to eight spores, with the wall and apical dome turning blue in response to potassium hydroxide and iodine. Ascospores are ellipsoidal, ovoid, or fusiform, sometimes featuring an apiculate end, and are septate and colourless. Lichen substances have not been detected by thin-layer chromatography in Leptogium species. [3]
As of April 2023 [update] , Species Fungorum (in the Catalogue of Life) accepts 84 species of Leptogium. [1]
Collema is a genus of lichens in the family Collemataceae. The photobiont is the cyanobacterium genus Nostoc. Species in this genus typically grow on nutrient-rich bark or somewhat siliceous or calcareous rocks in humid environments.
The Pannariaceae are a family of lichens in the order Peltigerales. Species from this family have a widespread distribution, but are especially prevalent in southern temperate regions.
The Collemataceae are a lichenized family of fungi in the order Peltigerales. The family contains ten genera and about 325 species. The family has a widespread distribution.
Acanthothecis is a genus of lichen-forming fungi in the family Graphidaceae. The genus was circumscribed by Frederick Edward Clements in 1909.
Psoroma is a genus of lichen-forming fungi in the family Pannariaceae. The widespread genus contains about 30 species, most of which are found in south temperate regions.
Parmeliella is a genus of lichenized fungi in the family Pannariaceae. It occurs mainly in the tropics and sub-tropics, with species found in Africa, Asia, Australasia and South America. A recent (2020) estimate places 41 species in the genus.
Pyxine is a genus of foliose lichens in the family Caliciaceae. The genus has a widespread distribution in tropical regions.
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.
Arctomia is a genus of lichen-forming fungi in the family Arctomiaceae. The genus was originally circumscribed by Theodor Magnus Fries in 1861. Arctomia has a circumpolar distribution.
Per Magnus Jørgensen is a Norwegian botanist and lichenologist, and Professor Emeritus of systematic botany at the University of Bergen. He is known for his work on the lichen families Pannariaceae and Collemataceae. Jørgensen was awarded the Acharius Medal in 2021 for his lifetime contributions to lichenology.
Scytinium is a genus of lichen-forming fungi in the family Collemataceae. It has 49 species. These lichens are typically found on basic rocks, soil, and trees, occasionally in association with mosses. Despite the morphological and ecological diversity within Scytinium, its species share similar ascospore features, such as shape and septation, as well as a small to medium-sized thallus with at least a partial cortex.
Lathagrium is a genus of lichen-forming fungi in the family Collemataceae. It has 10 species of gelatinous lichens. Species in this genus typically grow on calcareous rocks, often amidst mosses, but can also be found on siliceous or serpentine rocks, mortar, or soil.
Allographa is a genus of script lichens in the family Graphidaceae. It has nearly 200 species. Formally circumscribed in 1824 by François Fulgis Chevallier, Allographa was formerly included in Graphis, but was upgraded to generic status in 2018 by lichenologists Klaus Kalb and Robert Lücking.
Leptogium kalbii is a species of lichen in the family Collemataceae. It is found in Brazil, both in São Paulo State and in some Islands of Brazil.
Bathelium is a genus of lichen-forming fungi in the family Trypetheliaceae.
Rostania is a genus of lichen-forming fungi in the family Collemataceae. These lichens are primarily found on tree bark, occasionally on wood, with one species known to inhabit soil. The genus is characterized morphologically by having minute thalli made of hyphal tissue without a separate cortex, and the more or less cuboid-shaped ascospores.
Pallidogramme is a genus of lichen-forming fungi in the family Graphidaceae. It has 8 species of corticolous (bark-dwelling), crustose lichens.