''Evernia'' 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 bushy lichens in the family

Parmeliaceae The Parmeliaceae is a large and diverse family of Lecanoromycetes. With over 2700 species in 71 genera, it is the largest family of lichen-forming fungi. The most speciose genera in the family are the well-known groups: '' Xanthoparmelia'' ( 82 ...

. Oakmoss '' Evernia prunastri'' is used as a fixative agent in

Eau de Cologne Eau de Cologne (; German: ''Kölnisch Wasser'' ; meaning "Water from Cologne") or simply cologne is a perfume originating in Cologne, Germany. Originally mixed by Johann Maria Farina (Giovanni Maria Farina) in 1709, it has since come to be a gene ...

within the

perfume Perfume (, ) is a mixture of fragrance, fragrant essential oils or aroma compounds (fragrances), Fixative (perfumery), fixatives and solvents, usually in liquid form, used to give the human body, animals, food, objects, and living-spaces an agre ...

industry. It is green on top and white on bottom, and divides evenly into "forks"; it becomes very soft when wet. It is not to be confused with ''

Ramalina ''Ramalina'' is a genus of greenish fruticose lichens that grow in the form of flattened, strap-like branches. Members of the genus are commonly called strap lichensField Guide to California Lichens, Stephen Sharnoff, Yale University Press, 201 ...

'', which is straplike, stiff and bristly, green on top and bottom, and divides unevenly. ''Evernia'' is an abundant genus, found growing on trees."Evernia." Lichens.
/span> Oregon State University. Retrieved on 25 Sept 2007.

Description

''Evernia'' species form soft, shrubby to strap-shaped

thalli 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 either drape from bark or lie prostrate when growing on the ground. A spreading basal

holdfast Holdfast most often refers to: *Holdfast (biology), a root-like structure that anchors aquatic sessile organisms to their substrate *Holdfast (tool), a tool used to secure a workpiece to a workbench or anvil Holdfast or hold fast may also refer t ...

secures the thallus, from which numerous flattened branch repeatedly. In most species the lobes are angular and subtly ridged, but in ''E. prunastri'' they are distinctly two-sided (). Both upper and lower surfaces are , yet the underside is invariably paler. The upper surface often develops shallow pits, while the interior

medulla Medulla (Latin for "marrow") or medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ...

consists of a loosely woven mass of fungal

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 that gives the thallus its flexible texture. Green, single-celled algae (a photobiont) live between the

e and provide photosynthetic carbon to the partnership. Evernia_mesomorpha

Sexual reproduction Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote tha ...

in ''Evernia'' lichens occurs in small, disc-shaped 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 ...

) that arise on the lobe margins. These apothecia sit on short, stout stalks; their are chestnut-red and bordered by an irregular, scalloped rim formed from lichen tissue (the ). Inside each cylindrical

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 ...

develop eight colourless, single-celled

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 typical of the ''

Lecanora ''Lecanora'' is a genus of lichen commonly called rim lichens.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, Lichens in the genus '' Squamarina'' are also called rim lichens. Members of the genus have roughly c ...

'' group. Asexual

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 ...

s are produced sparingly: minute flask-like

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 ...

are immersed in the thallus surface and appear as tiny dark dots. Each pycnidium releases long, needle-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 ...

that can establish new individuals without the need for sexual fusion. The chemistry of ''Evernia'' is consistent and useful for identification. When a drop 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 ...

(KOH) solution is applied, the cortex stains yellow owing to the presence of the substance

atranorin Atranorin is a chemical substance produced by some species of lichen. It is a secondary metabolite belonging to a group of compounds known as depsides. Atranorin has analgesic, anti-inflammatory, antibacterial, antifungal, cytotoxic, antioxidant, ...

, and in some specimens

usnic acid Usnic acid is a naturally occurring dibenzofuran derivative found in several lichen species with the formula C18H16O7. It was first isolated by German scientist W. Knop in 1844 and first synthesized between 1933 and 1937 by Frank H. Curd and Al ...

is also present. The medulla usually contains evernic acid, but in some extra-European species this is replaced by divaricatic acid.

Species

* '' Evernia divaricata'' * '' Evernia esorediosa'' * '' Evernia illyrica'' * '' Evernia prunastri'' * '' Evernia mesomorpha''

References

{{Taxonbar, from=Q2700688 Parmeliaceae Lecanorales genera Lichen genera Taxa named by Erik Acharius Taxa described in 1809