''Punctelia punctilla'' is a species of foliose lichen in the family Parmeliaceae. It is found in Africa, South America, and North America, where it grows on bark and on rocks. The main characteristics that distinguish ''Punctelia punctilla'' from other species of ''

Punctelia ''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 ...

'' are the presence of isidia on the thallus surface, a pale brown thallus undersurface, and the presence of

lecanoric acid Lecanoric acid is a chemical produced by several species of lichen.ubChem - Lecanoric acid"> Lecanoric acid is classified as a polyphenol and a didepside and it functions as an antioxidant. The acid is named after the lichen ''Lecanora''. The acid ...

in the medulla.

Taxonomy

It was first formally described in 1977 as a new species by American lichenologist

Mason Hale Mason Ellsworth Hale, Jr. (September 23, 1929 – April 23, 1990) was one of the most prolific lichenologists of the 20th century. Many of his scholarly articles focused on the taxonomy of the family Parmeliaceae. Hale was one of the first liche ...

as ''Parmelia punctilla''. The type specimen was collected by

Ove Almborn Ove or OVE may refer to * Ove (given name) * Ové, a surname * Ove Peak in Antarctica *'' A Man Called Ove (novel)'', a novel by Fredrik Backman *''A Man Called Ove ''A Man Called Ove'' may refer to: * ''A Man Called Ove'' (novel), a 2012 novel b ...

in the

Cathedral Peak Cathedral Peak may be any of several mountains, typically those with steep sides and towers reminiscent of a cathedral. In the United States alone, the USGS identifies 17 summits named "Cathedral Peak". In other countries: *Cathedr ...

area of South Africa, where it was found growing on a rock in Indumeni forest. The altitude of the type locality was . Hildur Krog transferred it to the genus ''

'' in 1982. In 1997, Mónica Adler proposed to synonymize the taxon ''

Punctelia missouriensis ''Punctelia missouriensis'', commonly known as the mealy speckled shield lichen, is a species of foliose lichen in the family Parmeliaceae. It is found in the southeastern United States, where it grows on tree bark and on rocks. Taxonomy It ...

'' with ''P. punctilla''.

André Aptroot André Aptroot (Heemskerk, 1961) is a Dutch mycologist and lichenologist. In 1993 he did his PhD at the University of Utrecht under the supervision of Robbert Gradstein (nl). His dissertation was titled "Systematic studies on pyrenocarpous li ...

later rejected this proposal, suggesting sufficient morphological differences exist for ''P. missouriensis'' to warrant distinction as an independent species.

Description

''Punctelia punctilla'' has a light mineral grey foliose thallus with darker margins. It is tightly attached to 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 ...

. There are abundant

pseudocyphella Pseudocyphellae (singular ''pseudocyphella'') are structures in lichens that appear as tiny pores on the outer surface (the cortex of the lichen. They are caused when there is a break in the cortex of the lichen, and the medullary hyphae extend t ...

e on that thallus surface; they are white, rounded to elongated, and measure up to 0.5 mm. The isidia are dull and low, sometimes branched, and often originate in cracks or at the margins of the pseudocyphellae. The thallus undersurface is pale tan with darker margins. Rhizines are usually simple (i.e. unbranched) and more or less the same colour as the undersurface. Standard chemical spot tests can be used to help identify ''Punctelia punctilla''. In the medulla, these results are K-, KC+ red, and C+ red. The last of these tests indicates the presence of

. The upper cortex contains atranorin, which results in a yellow K+ reaction. Species similar in appearance to ''Punctelia punctilla'' include '' Punctelia rudecta'' and '' Punctelia eganii'', two North American

endemics Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

that are morphologically indistinguishable from each other.

Habitat and distribution

''Punctelia punctilla'' has been recorded growing on both bark and on rocks. First described from South Africa, it was later recorded from various locations in South America, including several provinces of Argentina ( Mendoza, Buenos Aires, Santiago, Corrientes, Córdoba, and Río Negro), Brazil ( São Paulo), and Venezuela. The lichen was first reported from the United States in 1989; the material was verified by Mason Hale. It was found growing on rocks at the base of a

rocky outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial ...

in southern coastal California, in Point Mugu State Park; this area has a Mediterranean climate. A

herbarium A herbarium (plural: herbaria) is a collection of preserved plant specimens and associated data used for scientific study. The specimens may be whole plants or plant parts; these will usually be in dried form mounted on a sheet of paper (called ...

specimen of ''Punctelia punctilla'' collected in Iowa was later assumed to be a misidentification. The lichen has also been recorded from the Mexican state

Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...

References

{{Taxonbar, from=Q10646758 punctilla Lichen species Lichens described in 1977 Lichens of Africa Lichens of South America Lichens of the Southwestern United States Taxa named by Mason Hale Fungi without expected TNC conservation status