''Leptorhaphis'' 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 Naetrocymbaceae. Members of the genus are commonly called birchbark dot lichens. The genus comprises eight recognized species that are widely distributed, primarily growing on the bark of

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

trees such as

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...

aspen Aspen is a common name for certain tree species in the Populus sect. Populus, of the ''Populus'' (poplar) genus. Species These species are called aspens: * ''Populus adenopoda'' – Chinese aspen (China, south of ''P. tremula'') * ''Populus da ...

, and

larch Larches are deciduous conifers in the genus ''Larix'', of the family Pinaceae (subfamily Laricoideae). Growing from tall, they are native to the cooler regions of the northern hemisphere, where they are found in lowland forests in the high la ...

. Most species lack a visible

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 ...

and are considered

saprobic Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ...

rather than truly

ized, as they generally do not form a stable partnership with

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

Taxonomy

The genus was

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 1855 by

Gustav Wilhelm Körber Gustav Wilhelm Körber (10 January 1817, Jelenia Góra, Hirschberg – 27 January 1885, Breslau) was a Silesian-German lichenologist and a professor at the University of Wrocław, University of Breslau. He specialized in the flora of Central Europ ...

, who assigned ''Leptorhaphis oxyspora'' as the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

. Körber distinguished ''Leptorhaphis'' from '' Arthopyrenia'' based on the elliptical-hemispherical to spherical

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 are innate-sessile with a distinctive distinctive hard, blackish outer wall that has a white, barely visible pore at the apex. The genus is characterised by having a colourless or faintly brownish gelatinous nucleus, greenish-brown rounded

paraphyses Paraphyses are erect sterile filament-like support structures occurring among the reproductive apparatuses of fungi, ferns, bryophytes and some thallophytes. The singular form of the word is paraphysis. In certain fungi, they are part of the f ...

, and 2–4 needle-like spores per

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 ...

that are colourless and contained within short asci. Körber noted that while this genus had recently become known and he agreed with Massalongo's principles for establishing new genera through essential methodological agreement, he believed that after conducting thorough spore studies, one could assume a closer relationship with the latter genus based on the specified spore form.

Description

Most species of ''Leptorhaphis'' appear to have no visible lichen body (

): the fungus lives largely within the outer bark of deciduous trees and shows at most a faint, smooth, pale-grey to greenish film that is poorly delimited. A true partnership with algae is generally absent, so the genus is regarded as

rather than lichen-forming, though fresh material occasionally shows scattered filaments of '' Trentepohlia'' near the fruit bodies and, in rare cases such as '' L. atomaria'', a thin, genuine thallus develops. The reproductive structures dominate the visible

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

. Scattered, sometimes coalescing

perithecia 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. Ascoc ...

begin immersed in the bark but soon push outward, becoming hemispherical to nipple-shaped black domes with a minute pore. Each perithecium is capped by a dark composed of tightly interlocking

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 stay unchanged 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; in squash mounts these hyphae form a distinctive, clypeate (shield-like) lattice, and marginal strands may radiate to produce a basal fringe. Inside, a paler lines the cavity, and a network of branched, anastomosing threads the clear hymenial gel, which

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 ...

from yellow-orange to pale blue in iodine. The asci are cylinders that typically house eight, sometimes up to sixteen, colourless

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. Those spores are thin-walled, gently curved to sigmoid rods with one to three cross-walls, a shape (-) that readily separates ''Leptorhaphis'' from related bark fungi. Asexual

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 in or barely protruding from the bark, release similar but smaller 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 ...

, while

secondary metabolite Secondary metabolites, also called ''specialised metabolites'', ''secondary products'', or ''natural products'', are organic compounds produced by any lifeform, e.g. bacteria, archaea, fungi, animals, or plants, which are not directly involved ...

s have not been detected in the genus.

Species

* '' Leptorhaphis atomaria'' * ''

Leptorhaphis epidermidis ''Leptorhaphis'' is a genus of lichens in the family Naetrocymbaceae. Members of the genus are commonly called birchbark dot lichens. The genus comprises eight recognized species that are widely distributed, primarily growing on the bark of d ...

'' * '' Leptorhaphis haematommatum'' * '' Leptorhaphis laricis'' * '' Leptorhaphis maggiana'' * '' Leptorhaphis novae-guineae'' * '' Leptorhaphis opuntiicola'' * '' Leptorhaphis tremulae''

References

{{Taxonbar, from=Q10559097 Pleosporales Dothideomycetes genera Lichen genera Taxa named by Gustav Wilhelm Körber Taxa described in 1855