''Punctelia caseana'' is a species of

foliose lichen A foliose lichen is a lichen with flat, leaf-like , which are generally not firmly bonded to the substrate on which it grows. It is one of the three most common growth forms of lichens. It typically has distinct upper and lower surfaces, each o ...

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'' ( 82 ...

. 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 Flowering plant, angiosperm trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal ecosystem, boreal latitudes they are mostly deciduous, but in tropics and subtropics mostl ...

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 sin ...

trees.

Taxonomy

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

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

was collected in the

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

reserve in

Atlantic County, New Jersey Atlantic County is a county located in the U.S. state of New Jersey. As of the 2020 census, the county was the state's 15th-most-populous county,specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''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 Hypha, filamentous fungus. Lichens are chiefly characterized by th ...

Description

The color of the upper surface of the

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 ...

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, habitat refers to the array of resources, 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 manifestation of its ...

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 or g ...

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

soredia Soredia are common reproduction, reproductive structures of lichens. Lichens asexual reproduction, reproduce asexually by employing simple fragmentation and production of soredia and isidia. Soredia are powdery propagules composed of fungus, fung ...

are coarse and large.

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 produced by the lichen are

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

, measuring 14–17 by 10–12

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 ...

. It contains the secondary compounds atranorin, chloroatroanorin, and lecanoric acid. The standard lichen spot test 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'' because the latter has

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 ...

rather than soredia. Two lookalikes, '' Punctelia perrituculata'' 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''. 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 an inventory of the global conservation status and extinction risk of biological ...

. 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 evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

References

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