''Elixjohnia'' 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

Teloschistaceae The Teloschistaceae are a large family (biology), family of mostly lichen-forming fungi belonging to the class (taxonomy), class Lecanoromycetes in the division (botany), division Ascomycota. The family has a cosmopolitan distribution, althoug ...

. It has four species of

saxicolous This glossary of mycology is a list of definitions of terms and concepts relevant to mycology, the study of fungi. Terms in common with other fields, if repeated here, generally focus on their mycology-specific meaning. Related terms can be found ...

(rock-dwelling),

crustose lichen Crustose lichens are lichens that form a crust which strongly adheres to the Substrate (biology), substrate (soil, rock, tree bark, etc.), making separation from the substrate impossible without destruction. The basic structure of crustose lichen ...

s that occur in

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

Taxonomy

''Elixjohnia'' 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 2017 by

Sergey Kondratyuk Sergey Yakovlevich Kondratyuk () (born 17 May 1959) is a Ukrainian botanist specialising in lichenology. His research deals with the taxonomy, floristics, ecology and geography of lichens and lichenicolous fungi. He has worked at the for mo ...

and Jae-Seoun Jur in 2017, with '' Elixjohnia jackelixii'' assigned 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 ...

. Phylogenetic analysis shows that the genus is in the large '' Sirenophila''-'' Teloschistopsis''-''Halophila'' sub

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

of the subfamily Teloschistoideae (family

). The genus name honours Australian chemist and lichenologist John A. ("Jack") Elix. The existence and phylogenetic structure of the genus was corroborated by

molecular A molecule is a group of two or more atoms that are held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, ...

work published by Wilk and colleagues in 2021.

Description

''Elixjohnia'' is characterised by a

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 ...

that is typically , presenting initial appearances of brownish or a dirty greenish yellow in sterile circles. These circles can be dull, smooth, and continuous in their peripheral zones, or may lack any zonation. The thallus is often notably thick, especially at its centre, but may also be evenly continuous. The texture varies, with some specimens being smooth and entire, while others are distinctly . Colours can range from whitish, yellowish, or greyish shades to brighter hues of red or reddish-orange. Over time, the upper surface can become cracked and eroded, occasionally revealing

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 ...

-like formations. In many cases, the

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 ...

, or inner tissue, is exposed through these cracks. Adjacent to the thallus is the , which can either be well-developed or completely absent. The , or spore-producing structures, are frequently observed and tend to be small in size. In some species, these apothecia are , at least initially, but can also be or in form. Their is often a brownish-orange or yellowish-brown shade, sometimes with hints of red or even transitioning to a dull orange or a bright scarlet. Microscopically, the (outer rim of the apothecium) is made of tissue. The , or sterile fungal filaments, contain oil cells of the bermaguiana-type. Typically, there are eight spores in 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 ...

, but it is not uncommon to find 2, 4, or 6 mature bipolar ascospores accompanied by aborted ones. These ascospores can range from narrowly to broadly

ellipsoid An ellipsoid is a surface that can be obtained from a sphere by deforming it by means of directional Scaling (geometry), scalings, or more generally, of an affine transformation. An ellipsoid is a quadric surface; that is, a Surface (mathemat ...

in shape. Finally, the , or asexual spores, are broad and either ellipsoid or , with measurements typically falling between 2–3 by 1.2–1.7

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

Parietin Parietin is the predominant cortical pigment of lichens in the genus '' Caloplaca'', a secondary product of the lichen '' Xanthoria parietina'', and a pigment found in the roots of curled dock (''Rumex crispus''). It has an orange-yellow color ...

is the major

lichen substance 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 ...

associated with this genus.

Habitat and distribution

''Elixjohnia'' species predominantly colonise exposed coastal rocks, including

quartzite Quartzite is a hard, non- foliated metamorphic rock that was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tecton ...

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

, and

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grain ...

. These lichens are typically found at or above the

high tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

level. It is not uncommon to find species such as ''E. jackelixii'' and ''E. gallowayi'' growing alongside each other. Additionally, they often share their habitat with species from various genera, including '' Tarasginia whinrayi'', '' T. tomareana'', '' Sirenophila eos'', '' Jackelixia ligulata'', '' Gondwania sublobulata'', and '' Caloplaca conranii''. Geographically, ''Elixjohnia'' species have an Australasian distribution, spanning across southern and southeastern Australia,

Tasmania Tasmania (; palawa kani: ''Lutruwita'') is an island States and territories of Australia, state of Australia. It is located to the south of the Mainland Australia, Australian mainland, and is separated from it by the Bass Strait. The sta ...

, and New Zealand.

Species

* '' Elixjohnia bermaguiana'' * '' Elixjohnia gallowayi'' * '' Elixjohnia jackelixii'' * '' Elixjohnia ovis-atra''

References

{{Taxonbar, from=Q43402899 Teloschistales Teloschistales genera Lichen genera Taxa described in 2017 Taxa named by Sergey Kondratyuk Taxa named by Ingvar Kärnefelt Taxa named by Arne Thell