''Cresponea'' 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 ...

s in the family

Opegraphaceae ''Opegraphaceae'' is a family of lichen-forming and lichenicolous fungi in the order Arthoniales. It was originally proposed by German lichenologist Ernst Stizenberger in 1862. It fell into disuse, but was resurrected in a molecular phylogenetic ...

. The genus,

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

in 1993, contains species that were formerly classified in ''

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 ...

''. ''Cresponea'' is widely distributed, but most species are found in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropic The subtropical zones or subtropics are geographical and climate zones immediately to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 3 ...

al regions. The genus is named in honor of the Spanish lichenologist

Ana Crespo Ana María Crespo de las Casas (born 30 March 1948, Santa Cruz de Tenerife) is a Spanish lichenologist noted for studying the phytosociology, taxonomy and floristics of Mediterranean lichens. She was awarded the 2012 Acharius Medal from the Int ...

Description

''Cresponea'' spreads as a thin, paint-like crust that merges with the surface of bark or, less often, rock. The

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 ...

can be smooth or cracked into an irregular mosaic, and on rare occasions it breaks into tiny, discrete . Colours range from chalk-white through pale grey to a muted green; some specimens show a narrow, dark brown margin where the fungal threads alone grow out beyond the . Because there is no separate , the fungal tissue lies directly over the , usually the filamentous

green alga The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ( ...

genus '' Trentepohlia'', which gives a faint orange tint when the surface is scratched. The lichen never produces

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 ...

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 ...

, so it relies on its sexual and asexual fruit bodies for dispersal. The sexual structures are small, button-like

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 ...

that sit on the thallus with a pinched base. They lack a rim of thallus tissue, instead showing a glossy, often crenulated rim (the ) that is conspicuously dark brown to black and remains free of the powdery bloom that coats many related genera. The starts flat, may become gently domed, and is dusted with a fine white or bluish , especially in young apothecia. Inside, the clear

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 blue or reddish in iodine and houses slender filaments whose club-shaped tips carry a dark brown cap; together these caps form a granular that turns yellow in

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 ...

solution. Each

ascus An ascus (; : asci) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some gen ...

releases eight long, spindle-shaped

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 divided by three to nineteen cross-walls (

septa SEPTA, the Southeastern Pennsylvania Transportation Authority, is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly four million people througho ...

); the walls are thick, and the spores stay colourless.

Asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the f ...

occurs in tiny

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 ...

embedded in the crust; these produce short, 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 ...

. Most species show no detectable

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 chemical

tests Test(s), testing, or TEST may refer to: * Test (assessment), an educational assessment intended to measure the respondents' knowledge or other abilities Arts and entertainment * ''Test'' (2013 film), an American film * ''Test'' (2014 film) ...

Ecology

Generally

epiphytic An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

, ''Cresponea'' lichen prefer mature, humid

woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunli ...

s and are sometimes used as an indicator of

old-growth An old-growth forest or primary forest is a forest that has developed over a long period of time without Disturbance (ecology), disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organizati ...

conditions, though a few species tolerate rock surfaces in sheltered sites.

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 23 species of ''Cresponea''. *'' Cresponea ancistrosporelloides'' *'' Cresponea apiculata'' *'' Cresponea chloroconia'' *'' Cresponea endosulphurea'' – Brazil *'' Cresponea flava'' *'' Cresponea flavescens'' *'' Cresponea flavosorediata'' – Brazil *'' Cresponea follmannii'' *'' Cresponea graemeannae'' *'' Cresponea japonica'' *'' Cresponea leprieurii'' *'' Cresponea leprieuroides'' *'' Cresponea lichenicola'' – Brazil *'' Cresponea litoralis'' – Australia *'' Cresponea macrocarpoides'' *'' Cresponea melanocheiloides'' *'' Cresponea pallidosorediata'' – Brazil *'' Cresponea plurilocularis'' *'' Cresponea premnea'' *'' Cresponea proximata'' *'' Cresponea quinqueseptata'' – Brazil *'' Cresponea sorediata'' *'' Cresponea subpremnea''

References

{{Taxonbar, from=Q5184485 Opegraphaceae Arthoniomycetes genera Lichen genera Taxa described in 1993