''Lathagrium'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

lichen A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualism (biology), m ...

-forming

fungi A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

in the family

Collemataceae The Collemataceae are a family of mostly lichen-forming fungi in the order Peltigerales. The family contains twelve genera and about 325 species. The family has a widespread distribution. Taxonomy The family was circumscribed by Jonathan Carl Z ...

. It has 10 species of gelatinous lichens. Species in this genus typically grow on

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime (mineral), lime or being chalky. The term is used in a wide variety of Science, scientific disciplines. In zoology ''Calcare ...

rocks, often amidst

moss Mosses are small, non-vascular plant, non-vascular flowerless plants in the taxonomic phylum, division Bryophyta (, ) ''sensu stricto''. Bryophyta (''sensu lato'', Wilhelm Philippe Schimper, Schimp. 1879) may also refer to the parent group bryo ...

es, but can also be found on

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant ...

or serpentine rocks, mortar, or soil.

Description

''Lathagrium'' is characterized by a

foliose A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common lichen growth forms, growth forms of lichens. It typically has distinct upper and lo ...

, medium to large-sized

thallus Thallus (: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. A thallus usually names the entir ...

that can appear gelatinous and may swell when wet. The color of the upper surface ranges from dark olive-green to brown-black and occasionally exhibits a grey-blue hue. The of the thallus can be narrow or broad, often elongated and intricately branched, with a flat or concave surface that can be smooth or distinctly ridged or folded. The thallus is composed of intertwined

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e intermingled with chains of cells, and it lacks both upper and lower . While

isidia An isidium (plural: isidia) is a tiny, wart- or finger-like outgrowth on the thallus surface of certain lichen species. It is one of two principal types of vegetative reproduction, vegetative reproductive structures in lichens, the other being ...

can be absent or frequently present,

soredia Soredia are common reproduction, reproductive structures of lichens. Lichens asexual reproduction, reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungus, fung ...

are not found in ''Lathagrium''. The reproductive structures, called

apothecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. As ...

, display a pale brown, red-brown, or brown-black surrounded by a that is typically long-lasting. The internal structure of the apothecia consists of colourless or pigmented , a colorless

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

that turns blue when treated with

iodine Iodine is a chemical element; it has symbol I and atomic number 53. The heaviest of the stable halogens, it exists at standard conditions as a semi-lustrous, non-metallic solid that melts to form a deep violet liquid at , and boils to a vi ...

, and a nearly colorless . The contains that separate in a solution of

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...

and may be unbranched or branched, often connecting near the apices. The tips of the paraphyses can be club-shaped or round and display a yellowish to reddish-brown colour. The asci, or spore-producing structures, are club-shaped (clavate) with a significantly thickened apex that reacts blue with iodine, as does the downwardly projecting annulus and apical cap. ''Lathagrium'' produces eight spores per ascus, which are

septate In biology, a septum (Latin for ''something that encloses''; septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatrial se ...

and primarily , but can also be spindle-shaped or cylindrical with only transverse septa. , or , are generally embedded within the thallus and can be found on the margins or with a pale

ostiole An ''ostiole'' is a small hole or opening through which algae or fungi release their mature spores. The word is a diminutive of wikt:ostium, "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the ...

. The conidia are rod-shaped and may be slightly enlarged at the apex. Chemical analysis using

thin-layer chromatography Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the sta ...

has not detected any

lichen product Lichen products, also known as lichen substances, are organic compounds produced by a lichen. Specifically, they are secondary metabolites. Lichen products are represented in several different chemical classes, including terpenoids, orcinol deri ...

s in ''Lathagrium''.

Species

*'' Lathagrium auriforme'' *'' Lathagrium cristatum'' *'' Lathagrium dichotomum'' *'' Lathagrium durietzii'' *'' Lathagrium fuscovirens'' *'' Lathagrium latzelii'' *'' Lathagrium neglectum'' *'' Lathagrium poeltii'' *'' Lathagrium subundulatum'' *'' Lathagrium undulatum''

References

{{Taxonbar, from=Q23768216 Peltigerales Lichen genera Taxa described in 1810 Taxa named by Erik Acharius Peltigerales genera