''Allocalicium'' is a lichen genus in the family

Caliciaceae The Caliciaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. Although the family has had its classification changed several times throughout its taxonomic history, the use of m ...

. It is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

, containing the single pin lichen species ''Allocalicium adaequatum''.

Taxonomy

''Allocalicium'' was

circumscribed In geometry, the circumscribed circle or circumcircle of a polygon is a circle that passes through all the vertices of the polygon. The center of this circle is called the circumcenter and its radius is called the circumradius. Not every po ...

in 2016 by lichenologists Maria Prieto and Mats Wedin, to contain the single species ''Allocalicium adaequatum''. This lichen was originally called ''Calicium adaequatum'' when it was first described by

William Nylander William Andrew Michael Junior Nylander Altelius (born 1 May 1996) is a Canadian-born Swedish professional ice hockey right winger for the Toronto Maple Leafs of the National Hockey League (NHL). Nylander was selected by the Maple Leafs in the ...

in 1869. In an analysis of the

systematics Biological systematics is the study of the diversification of living forms, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees (synonyms: cladograms, phylogenetic t ...

of the Caliciaceae using

molecular phylogenetics Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

, Prieto and Wedin discovered that the lichen was one of several ''

Calicium ''Calicium'' is a genus of leprose lichens. It is in the family Caliciaceae. The sexual reproduction structures are a mass of loose ascospores that are enclosed by a cup shaped exciple sitting on top of a tiny stalk, having the appearance ...

'' species that did not group with other members of the genus. The generic name ''Allocalicium'' combines the Greek prefix ''allo'' ("strange") with the name of its former genus.

Description

''Allocalicium'' has a

thallus Thallus (plural: 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. Many of these organisms ...

that is immersed in its

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 (locomotion), the surface over which an organism lo ...

. It has a pale grey to olive brown stalk that is 8–10 times as high as its diameter. Its

ascomata An ascocarp, or ascoma (), 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. Ascocarps are mo ...

have olive-brown stalks that form small clumps. The capitulum (the expanded, upper part of the stalk) is bell-shaped and dark. The excipulum (the base upon which rests 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 others som ...

) is 20–35

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...

thick, and brown on its outermost parts.

Spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

have a single

septum In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interat ...

, and measure 11 by 4.5–5.5 μm. They feature an ornamentation of spirally arranged ridges. ''Allocalicium'' is closely related to ''

Tholurna ''Tholurna'' is a genus of lichenized fungi in the family Caliciaceae. The genus is monotypic, containing the single species ''Tholurna dissimilis''. This species was first described by Johannes Musaeus Norman as ''Podocratera dissimilis'' in 1 ...

'', and both have quite similar spore ornamentation and capitulum

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, ...

. The relatedness of the two genera had been mentioned in 2003 by

Leif Tibell Leif Tibell (born 16 November 1944) is a Swedish lichenologist and Emeritus Professor at the University of Uppsala. He is known for his expertise on calicioid lichens. He was awarded the Acharius Medal in 2012 for lifetime achievements in l ...

, who suggested that the genus ''Calicium'', as it was then circumscribed, was

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

Habitat and distribution

''Allocalicium adaequatum'' grows on thin branches of the species ''

Alnus incana ''Alnus incana'', the grey alder or speckled alder, is a species of multi-stemmed, shrubby tree in the birch family, with a wide range across the cooler parts of the Northern Hemisphere. Tolerant of wetter soils, it can slowly spread with runners ...

'', ''

Populus ''Populus'' is a genus of 25–30 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. English names variously applied to different species include poplar (), aspen, and cottonwood. The we ...

'', and ''

Salix Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...

''. It prefers locales with high humidity, and is often found along streams in well-lit areas of swamps.

References

{{Taxonbar, from= Q105409584 Caliciales Lichen genera Monotypic Lecanoromycetes genera Taxa described in 2016