''Alyxoria'' 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

Lecanographaceae ''Lecanographaceae'' is a family of mostly lichens (also some lichenicolous fungi) in the order Arthoniales. The family was circumscribed in 2014, prompted by a molecular phylogenetic-based restructuring of the Arthoniales. Taxonomy The fami ...

. The genus has a

cosmopolitan distribution In biogeography, a cosmopolitan distribution is the range of a taxon that extends across most or all of the surface of the Earth, in appropriate habitats; most cosmopolitan species are known to be highly adaptable to a range of climatic and en ...

. These lichens are often so inconspicuous that they appear as little more than faint cracks or weathered patches on tree bark and rock surfaces, making them easily overlooked in the field. The genus includes about 20 species that reproduce through distinctive elongated slits containing

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, and can also spread asexually through tiny flask-shaped structures that release microscopic

propagule In biology, a propagule is any material that functions in propagating an organism to the next stage in its life cycle, such as by dispersal. The propagule is usually distinct in form from the parent organism. Propagules are produced by organisms ...

Description

''Alyxoria'' typically forms a very thin, often barely visible crust that infiltrates the surface of the bark or rock rather than sitting on top of it. In some species the thallus is so reduced that it soon weathers away, leaving only scattered patches or a faint network of cracks ( texture) against the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

. Where the crust is intact it appears smooth, and a

hand lens A magnifying glass is a convex lens—usually mounted in a frame with a handle—that is used to produce a magnification, magnified image of an object. A magnifying glass can also be used to focus light, such as to concentrate the Sun's radiati ...

may reveal the orange tinge that betrays the presence of the microscopic filamentous alga '' Trentepohlia'', which supplies the lichen's

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. The sexual fruit bodies are elongated slits called . These may be straight, gently curved, or occasionally branch to form a star-like outline, and the tips usually taper to fine points. They lack a surrounding rim of thallus tissue (); instead the —their own wall—is thin and chestnut-brown, often glazed with a frost of minute crystals (pruinose). As the lirellae mature the surface becomes exposed and can gape slightly. Inside, the

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 ...

contains many slender filaments () that fork and re-join repeatedly, creating a loose mesh; unlike some relatives, their tips rarely swell. 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 ...

carries eight long, spindle-shaped spores that are divided by several cross-walls. When young the spores are colourless and wrapped in a clear, gelatinous envelope, but with age they can darken and develop minute wart-like bumps before finally disintegrating.

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 tiny flask-shaped structures (

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 or sitting on the thallus. These release very small, 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 ...

through a pore at the top, enabling the fungus to disperse independently of its algal partner. Chemical spot tests are of limited use in the genus: most species show no significant colour reactions and

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 revealed few diagnostic

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 ...

Species

*'' Alyxoria apomelaena'' *'' Alyxoria bicolor'' *'' Alyxoria culmigena'' *'' Alyxoria cyanea'' – Brazil *'' Alyxoria diaphora'' *'' Alyxoria fuscospora'' – Brazil *'' Alyxoria lichenoides'' *'' Alyxoria lutulenta'' *'' Alyxoria mougeotii'' *'' Alyxoria notha'' *'' Alyxoria ochrocheila'' *'' Alyxoria ochrocincta'' *'' Alyxoria sierramadrensis'' – Mexico *'' Alyxoria subelevata'' *'' Alyxoria subrimalis'' *'' Alyxoria varia'' *'' Alyxoria variiformis'' *'' Alyxoria viridipruinosa'' *'' Alyxoria wainioi'' *'' Alyxoria xerica''

References

{{Taxonbar, from=Q21216944 Lecanographaceae Lichen genera Arthoniomycetes genera Taxa described in 1821 Taxa named by Samuel Frederick Gray