''Punctelia caseana'' is a species of

foliose lichen Foliose lichen is one of the morphological classes of lichens, which are complex organisms that arise from the symbiotic relationship between fungi and a photosynthetic partner, typically algae. This partnership allows lichen to live in diverse ...

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'' ( 822 ...

. Its range covers eastern North America, extending south to central and northern Mexico, where it grows on the bark of many species of

hardwood Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...

and

conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

trees.

Taxonomy

''Punctelia caseana'' was described as a new species in 2010 by lichenologists James Lendemer and Brendan Hodkinson. The type was collected in the

Nature Conservancy The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US. Founded in 1951, The Natu ...

reserve in

Atlantic County, New Jersey Atlantic County is a county located along the southern coast of the U.S. state of New Jersey. As of the 2020 U.S. census, the county had a population of 274,534.specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''caseana'' honors Martha A. Case, who was an undergraduate professor of Hodkinson and encouraged his interest in

lichenology Lichenology is the branch of mycology that studies the lichens, symbiotic organisms made up of an intimate symbiotic association of a microscopic alga (or a cyanobacterium) with a filamentous fungus. Study of lichens draws knowledge from several ...

Description

The color of the upper surface of the

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 ...

of ''Punctelia caseana'' is grey-blue, while the undersurface is pale to off-white, sometimes light brown. The size of the thallus is quite variable, depending largely on the

microhabitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

conditions. There are many

soralia Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria o ...

, which are mostly located along the margins of the lobes. The

soredia Soredia are common reproductive structures of lichens. Lichens reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungal hyphae wrapped around cyanobacteria or gr ...

are coarse and large.

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 produced by the lichen are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

, measuring 14–17 by 10–12

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 Unit ...

. It contains the

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

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, ...

, chloroatroanorin, and lecanoric acid. The standard

lichen spot test A spot test in lichenology is a spot analysis used to help identify lichens. It is performed by placing a drop of a chemical on different parts of the lichen and noting the colour change (or lack thereof) associated with application of the chemical ...

results are K+ (yellow), C−, KC−, P−, and UV− in the upper

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

; in the medulla they are K−, KC+ (red), C+ (red), P−, and UV−. ''Punctelia caseana'' can be readily distinguished from the common North American species ''

Punctelia rudecta ''Punctelia rudecta'', commonly known as the rough speckled shield or the speckleback lichen, is a North American species of foliose lichen in the family Parmeliaceae. This species can be readily identified by the light color of the thallus u ...

'' because the latter has

isidia An isidium is a vegetative reproductive structure present in some lichens. Isidia are outgrowths of the thallus surface, and are corticated (i.e., containing the outermost layer of the thallus), usually with a columnar structure, and consisting o ...

rather than soredia. Two lookalikes, ''

Punctelia perrituculata ''Punctelia'' is a genus of foliose lichens belonging to the large family Parmeliaceae. The genus, which contains about 50 species, was segregated from genus ''Parmelia'' in 1982. Characteristics that define ''Punctelia'' include the presence of ...

'' and '' P. subrudecta'', both produce medullary gyrophoric acid and have a pale lower surface, like ''Punctelia caseana''. However, they have short conidia, and ''P. perrituculata'' has a surface texture covered with small round pits or grooves (''scrobiculae'').

Habitat and distribution

It is found in the eastern United States on many types of

trees, as well as

s, and occasionally on rotting logs. Its distribution in the eastern US is similar to that of ''

Punctelia subrudecta ''Punctelia subrudecta'' is a species of lichen in the family Parmeliaceae. It was described as a new species by Finnish lichenologist William Nylander as ''Parmelia subrudecta''. Hildur Krog Hildur Krog (22 March 1922 – 25 August 2014) was a ...

''. The range of ''Punctelia caseana'' was later extended to include eastern and central Mexico.

Conservation

In 2021, ''Punctelia caseana'' was assessed for the global

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

. Because it has an abundant and widespread population in North America with no sign of decline, it is considered a species of

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

References

{{Taxonbar, from=Q10646737 caseana Lichen species Lichens described in 2010 Lichens of Mexico Lichens of the United States