''Schismatomma'' 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 ...

of mostly

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

Roccellaceae The Roccellaceae are a family (biology), family of mostly lichen-forming fungi in the order Arthoniales, established by the French botanist François Fulgis Chevallier in 1826. Species in the family exhibit various lichen growth forms, growth ...

. These lichens form thin crusts on bark or rock surfaces and reproduce through disc-shaped

fruiting bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

that release

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s, as well as through powdery patches that help them spread. At least one species is

critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

due to

habitat loss Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...

from

deforestation Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...

in Colombia.

Description

''Schismatomma'' species form a thin, crust-like

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 lies more or less flush with the bark or rock surface. Where colonies meet they may be separated by a dark brown to black fringe (the ), and some species develop powdery reproductive patches called

soralia Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or g ...

that can mask the underlying crust. A quick scratch of fresh material exposes an orange stain—pigment from the filamentous alga '' Trentepohlia'', which supplies the

photosynthetic Photosynthesis ( ) is a Biological system, system of biological processes by which Photoautotrophism, photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical ener ...

partner in every species. Because the crust lacks a true outer skin () the sits immediately beneath the fungal tissue. Sexual fruit bodies (

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 ...

) start embedded in the thallus but often emerge to become small, slightly irregular . Each is ringed by a rim of thallus tissue (), while the fruit body's own wall () remains poorly developed and soon blends into the surrounding crust. Internally, the spore-bearing layer (

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 ...

)

stains A stain is an unwanted localized discoloration, often in fabrics or textiles. Stain(s) or The Stain(s) may also refer to: Color * Stain (heraldry), a non-standard tincture * Staining, in biology, a technique used to highlight contrast in samples ...

blue in iodine and is threaded by branched, interwoven filaments (). Beneath lies a dark olive to black that may be scarcely visible in thin specimens. The asci are club-shaped and split open () to release eight spindle-shaped to gently curved

ascospore In fungi, an ascospore is the sexual spore formed inside an ascus—the sac-like cell that defines the division Ascomycota, the largest and most diverse Division (botany), division of fungi. After two parental cell nucleus, nuclei fuse, the ascu ...

s, each divided by several cross-walls; the spores are colourless when young, may brown slightly with age, and can coil inside the ascus before discharge.

Asexual propagation Plant propagation is the process by which new plants grow from various sources, including seeds, cuttings, and other plant parts. Plant propagation can refer to both man-made and natural processes. Propagation typically occurs as a step in the o ...

occurs in flask-shaped

pycnidia A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi, for instance in the order Sphaeropsidales ( Deuteromycota, Coelomycetes) or order Pleosporales (Ascomycota, Dothideomycetes). It is often spherical or inve ...

sunk within the thallus. Their lining cells bud off minute, rod-shaped

conidia A conidium ( ; : conidia), sometimes termed an asexual chlamydospore or chlamydoconidium (: chlamydoconidia), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also ...

—straight, curved, or kidney-shaped—that escape through a tiny pore and disperse independently of the alga. Chemical analysis shows wide variation: different species may contain

orcinol Orcinol is an organic compound with the formula CH3C6H3(OH)2. It occurs in many species of lichens including ''Roccella tinctoria'' and ''Lecanora''. Orcinol has been detected in the "toxic glue" of the ant species ''Camponotus saundersi''. It is ...

-type

depside A depside is a type of polyphenolic compound composed of two or more monocyclic aromatic units linked by an ester group. Depsides are most often found in lichens, but have also been isolated from higher plants, including species of the Ericaceae, ...

s such as

lecanoric acid Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside, and it functions as an antioxidant. It is an ester of orsellinic acid with itself. The acid ...

or erythrin, β-

compounds like fumarprotocetraric or

psoromic acid Psoromic acid is a β-orcinol depsidone with the molecular formula C18H14O8. Psoromic acid inhibits herpes simplex viruses type 1 and type 2. Furthermore, it inhibits the RabGGTase. Psoromic acid occurs in antarctic lichens A lichen ( , ) ...

s, yellow

chromone Chromone (or 1,4-benzopyrone) is a derivative of benzopyran with a substituted keto group on the pyran ring. It is an isomer of coumarin. Derivatives of chromone are collectively known as ''chromones''. Most, though not all, chromones are also ...

fatty acid In chemistry, in particular in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an ...

s, or remain chemically undetected. Morphologically the genus resembles ''

Enterographa ''Enterographa'' is a genus of lichens in the family Roccellaceae. These lichens grow as thin, paint-like crusts on tree bark that range in colour from off-white and pale grey to dark olive-green or brown, sometimes breaking into networks of t ...

'' and ''

Lecanactis ''Lecanactis'' is a genus of crustose lichens, commonly called old wood lichens. The mycobiont (fungus partner) is in the family Roccellaceae. The photobiont is an algae in the genus '' Trentepohlia''. These lichens typically grow as thin crus ...

'', but it is set apart by the presence of a thalline margin around the apothecia and a much reduced exciple.

Conservation

'' Schismatomma leucopsarum'' was assessed as a

Critically Endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...

species in 2023 for the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

. The lichen is known from only a single location in the municipality of Honda,

Cundinamarca Department Department of Cundinamarca (, ) is one of the departments of Colombia. Its area covers (not including the Capital District) and it has a population of 2,919,060 as of 2018. It was created on August 5, 1886, under the constitutional terms pre ...

, where it is threatened by

for timber extraction and expansion of industrial areas. Despite surveys in similar habitats, the species has not been rediscovered since its initial collection.

Species

Species Fungorum ''Index Fungorum'' is an international project to index all formal names (Binomial nomenclature, scientific names) in the fungus Kingdom (biology), kingdom. As of 2015, the project is based at the Royal Botanic Gardens, Kew, one of three partn ...

(in the

Catalogue of Life The Catalogue of Life (CoL) is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxono ...

) accepts seven species of ''Schismatomma'', although many more

taxa In biology, a taxon (back-formation from ''taxonomy''; : taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and ...

than this have been named as members of the genus. * '' Schismatomma dolosum'' * '' Schismatomma glaucescens'' * ''

Schismatomma graphidioides ''Schismatomma'' is a genus of mostly lichen-forming fungi in the family Roccellaceae. These lichens form thin crusts on bark or rock surfaces and reproduce through disc-shaped fruiting bodies that release spores, as well as through powdery pa ...

'' * '' Schismatomma insulae-howense'' * '' Schismatomma leucopsarum'' * '' Schismatomma occultum'' * '' Schismatomma physconiicola'' * '' Schismatomma umbrinum''

References

{{Taxonbar, from=Q7431503 Roccellaceae Lichen genera Arthoniomycetes genera Taxa named by Abramo Bartolommeo Massalongo Taxa described in 1852