''Verrucula'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of lichenicolous (lichen-dwelling)

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Verrucariaceae The Verrucariaceae are a family of mostly lichenised fungi in the order Verrucariales. The lichen-forming species, which comprise the vast majority of the family, have a wide variety of thallus forms, and include crustose (crust-like), foliose ( ...

. Species in the genus are parasitic on saxicolous (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, including ''

Xanthoria elegans ''Xanthoria elegans'', commonly known as the elegant sunburst lichen, is a lichenized species of fungus in the genus ''Xanthoria'', family Teloschistaceae. Recognized by its bright orange or red pigmentation, this species grows on rocks, often ne ...

'' as well as lichens from genus ''

Caloplaca ''Caloplaca'' is a lichen genus comprising a number of distinct species. Members of the genus are commonly called firedot lichen, jewel lichen.Field Guide to California Lichens, Stephen Sharnoff, Yale University Press, 2014, gold lichens, "ora ...

'' that contain

chemical substances A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent Chemical element, elements by physical separation m ...

called anthraquinones.

Taxonomy

''Verrucula'' was originally

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 polyg ...

in 1896 by Austrian lichenologist

Julius Steiner The gens Julia (''gēns Iūlia'', ) was one of the most prominent patrician families in ancient Rome. Members of the gens attained the highest dignities of the state in the earliest times of the Republic. The first of the family to obtain the c ...

to contain a group of parasitic ''

Verrucaria ''Verrucaria'' is a genus of lichenized (lichen-forming) fungi in the family Verrucariaceae. Taxonomy The genus was circumscribed by German botanist Heinrich Adolph Schrader in 1794, with '' Verrucaria rupestris'' assigned as the type species. I ...

'' species. It was subsequently little used until 2007, when it was resurrected for use for ''Verrucaria'' found as parasites on ''

'' with anthraquinone compounds. Other parasitic species were moved to genus ''

Verruculopsis ''Verruculopsis'' is a genus of saxicolous lichen, saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. It was circumscription (taxonomy), circumscribed in 2007 by Cécile Gueidan, Pere Navarro-Rosinés, and Claude Roux, wit ...

''; these two genera are morphologically quite similar.

Molecular phylogenetic 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 ...

analysis shows that ''Verrucula'' has a

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

relationship with ''

Placocarpus ''Placocarpus'' is a genus of lichens in the family Verrucariaceae. The genus was circumscribed by Italian botanist Vittore Benedetto Antonio Trevisan de Saint-Léon Vittore Benedetto Antonio Trevisan de Saint-Léon (5 June 1818, in Padua &nd ...

'' in the family Verrucariaceae.

Description

''Verrucula'' lichens have 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 wer ...

that is

areolate Lichens are composite organisms made up of multiple species: a fungal partner, one or more photosynthetic partners, and sometimes a basidiomycete yeast. They are regularly grouped by their external appearance – a characteristic known as their ...

to a mixture of

squamulose A squamulose lichen is a lichen that is composed of small, often overlapping "scales" called squamules. If they are raised from the substrate and appear leafy, the lichen may appear to be a foliose lichen, but the underside does not have a "skin ...

and areolate, and is sometimes reduced in form. The upper cortex is only weakly developed, and is termed a pseudocortex. The excipulum (the ring-shaped layer surrounding 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 some ...

) is pale except for the pale to pale brown area around the

ostiole An ''ostiole'' is a small hole or opening through which algae or fungi release their mature spores. The word is a diminutive of "ostium", "opening". The term is also used in higher plants, for example to denote the opening of the involuted ...

Ascospore An ascus (; ) 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 genera or s ...

s are colorless, and usually simple, although in rare instances they 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 * Interatri ...

. Pycnidia in ''Verrucula'' are similar in form to those found in genus ''

Dermatocarpon ''Dermatocarpon'' is a genus of lichens in the family Verrucariaceae. Members of the genus are commonly called stippleback lichens because they have fruiting structures called perithecia that are flask-shaped structures embedded in the nonfruiti ...

''. This is pycnidial type is characterised by its paraplectenchymatous net (paraplectenchyma is a fungal tissue with a cellular structure superficially like the

parenchyma Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word π ...

vascular plants Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...

) and its multiple cavities.

Species

, Species Fungorum accepts 16 species of ''Verrucula''. The following list gives the species name, author citation (using standard abbreviations), year of publication, and host lichen. The

host specificity In biology and medicine, a host is a larger organism that harbours a smaller organism; whether a parasitic, a mutualistic, or a commensalist ''guest'' (symbiont). The guest is typically provided with nourishment and shelter. Examples include a ...

in genus ''Verrucula'' is quite high, as each species seems to parasitise a single host. * '' Verrucula arnoldaria'' – '' Calogaya arnoldii'' * '' Verrucula biatorinaria'' – ''

Calogaya biatorina ''Calogaya'' is a genus of lichen-forming fungi belonging to the family Teloschistaceae. It has 19 species. The genus was circumscription (taxonomy), circumscribed in 2013 by Ulf Arup, Ulrik Søchting, and Patrik Frödén. The generic name ''Cal ...

'' * '' Verrucula clauzadaria'' – '' Caloplaca clauzadeana'' * '' Verrucula coccinearia'' – '' Caloplaca coccinea'' * '' Verrucula coronataria'' – ''

Flavoplaca coronata ''Flavoplaca'' is a genus of crust-like or scaly lichens in the family Teloschistaceae. It has 28 species with a mostly Northern Hemisphere distribution. Taxonomy The genus was circumscribed in 2013 by Ulf Arup, Patrik Frödén and Ulrik Søch ...

'' * '' Verrucula elegantaria'' – ''

'' * '' Verrucula helvetica'' – '' Leproplaca cirrochroa'' * '' Verrucula hladuniana'' – ''

Flavoplaca marina ''Flavoplaca'' is a genus of crust-like or scaly lichens in the family Teloschistaceae. It has 28 species with a mostly Northern Hemisphere distribution. Taxonomy The genus was circumscribed in 2013 by Ulf Arup, Patrik Frödén and Ulrik Søch ...

'' * '' Verrucula inconnexaria'' – '' Caloplaca inconnexa'' * '' Verrucula lactearia'' – '' Xanthocarpia lactea'' * '' Verrucula maritimaria'' – ''

Flavoplaca maritima ''Flavoplaca maritima'' is a species of crustose lichen in the family Teloschistaceae. It is found in costal areas of Northern, Western, and Southern Europe. It mostly occurs on rocks, but has also been recorded growing on wood. Taxonomy It ...

'' * '' Verrucula microspora'' – ''

Variospora velana ''Variospora'' is a genus of crustose lichens, belonging to the family Teloschistaceae. The genus was circumscription (taxonomy), circumscribed in 2013 by Ulf Arup, Ulrik Søchting, and Patrik Frödén. Species *''Variospora aegaea'' *''Vario ...

'' * '' Verrucula navasianaria'' – ''

Flavoplaca navasiana ''Flavoplaca'' is a genus of crust-like or scaly lichens in the family Teloschistaceae. It has 28 species with a mostly Northern Hemisphere distribution. Taxonomy The genus was circumscribed in 2013 by Ulf Arup, Patrik Frödén and Ulrik Søch ...

'' * '' Verrucula polycarparia'' – ''

Flavoplaca polycarpa ''Flavoplaca'' is a genus of crust-like or scaly lichens in the family Teloschistaceae. It has 28 species with a mostly Northern Hemisphere distribution. Taxonomy The genus was circumscribed in 2013 by Ulf Arup, Patrik Frödén and Ulrik Søch ...

'' * '' Verrucula protearia'' – '' Leproplaca proteus'' * '' Verrucula pusillaria'' – ''

Calogaya pusilla ''Calogaya pusilla'' is a species of saxicolous (rock-dwelling), crustose lichen in the family Teloschistaceae. It was originally formally described in 1852 by Italian lichenologist Abramo Bartolommeo Massalongo, who placed it in genus ''Physcia ...

'' Some species previously classified in ''Verrucula'' have since been reduced to synonymy with other species, or have been transferred to different genera: *''Verrucula ahlesiana'' (= '' Laestadia ahlesiana'') *''Verrucula cahirensis'' (= '' Guignardia cahirensis'') *''Verrucula egyptiaca'' (= '' Guignardia egyptiaca'') *''Verrucula fraudulosa'' (= ''

Verruculopsis lecideoides ''Verruculopsis'' is a genus of saxicolous (rock-dwelling), crustose lichens in the family Verrucariaceae. It was circumscribed in 2007 by Cécile Gueidan, Pere Navarro-Rosinés, and Claude Roux, with '' Verruculopsis poeltiana'' assigned as the ...

'') *''Verrucula fuscella'' (= '' Verrucaria fuscella'') *''Verrucula granulosaria'' (= '' Verrucaria latericola'') *''Verrucula latericola'' (= '' Verrucaria latericola'') *''Verrucula lecideoides'' (= ''

'') *''Verrucula rheitrophila'' (= '' Hydropunctaria rheitrophila'')

References

{{Taxonbar, from=Q10714475 Verrucariales Eurotiomycetes genera Taxa described in 1896 Lichenicolous fungi