''Psilolechia'' 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 ...

of four species of

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. It is the only member of Psilolechiaceae, a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

that was created in 2014 to contain this genus.

Taxonomy

The genus ''Psilolechia'' was established by

Abramo Bartolommeo Massalongo Abramo Bartolommeo Massalongo (13 May 1824 – 25 May 1860) was an Italian paleobotanist and lichenologist. He was born in Tregnago in the Province of Verona and took a great interest in botany as a young man. Massalongo joined the faculty of med ...

in 1860. Formerly classified in the family

Pilocarpaceae The Pilocarpaceae are a family of crustose lichens in the order Lecanorales. The species of this family have a cosmopolitan distribution and have been found in a variety of climatic regions. Pilocarpaceae was circumscribed by Alexander Zahlbruck ...

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 showed that ''Psilolechia'' represented a distinct lineage that deserved placement at the familial level, the Psilolechiaceae, which was formally

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 2014. This arrangement was accepted in later large-scale updates of fungal classification. Psilolechiaceae is in the order

Lecanorales The Lecanorales are an order of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. The order contains 26 families, 269 genera, and 5695 species. Families Suborder Lecanorineae * Biatorellacea ...

, in the suborder Sphaerophorineae, which also includes the families

Psoraceae The Psoraceae are a family of lichenized fungi in the order Lecanorales. The Austrian Botanist and Lichenologist Alexander Zahlbruckner first described the family in 1898. Species of this family have a widespread distribution. Genera This is a ...

, and

Ramalinaceae The Ramalinaceae are a family of lichen-forming fungi in the order Lecanorales. First proposed by Carl Adolph Agardh in 1821, the family now comprises 63 genera and about 750 species. Ramalinaceae lichens exhibit diverse growth forms, includin ...

Description

Psilolechiaceae is a monogeneric family of

s with effuse, ecorticate (lacking a

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 ...

), leprose thalli formed by goniocysts (aggregations of

photobiont A lichen ( , ) is a hybrid colony of algae or cyanobacteria living symbiotically among filaments of multiple fungus species, along with yeasts and bacteria embedded in the cortex or "skin", in a mutualistic relationship.

cells surrounded by short-celled

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e) containing ''

Trebouxia ''Trebouxia'' is a unicellular green alga. It is a photosynthetic organism that can exist in almost all habitats found in polar, tropical, and temperate regions.Erokhina, L. G., Shatilovich, A. V., Kaminskaya, O. P., & Gilichinskii, D. A. (2004 ...

'' or stichococcoid algae. The

apothecia An ascocarp, or ascoma (: ascomata), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. As ...

lack a distinct margin, and the asci are 8-spored and have a cylindrical to clavate shape. They feature a central, elongated tube-like structure, and a non-

amyloid Amyloids are aggregates of proteins characterised by a fibrillar morphology of typically 7–13 nm in diameter, a β-sheet secondary structure (known as cross-β) and ability to be stained by particular dyes, such as Congo red. In the human ...

ascus wall surrounded by a thin outer layer. Both the tube-like structure and the thin outer layer

stain A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make materials app ...

dark blue in K/I.

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 are oblong-ovoid to tear-shaped, simple (rarely 1-septate in ''P. leprosa''), and

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 ...

Species

''Psilolechia'' contains four species: *'' Psilolechia clavulifera'' (Nyl.) Coppins (1983) – widespread *'' Psilolechia leprosa'' Coppins & Purvis (1987) – north-west Europe; Greenland *''

Psilolechia lucida ''Psilolechia lucida'' is a species of saxicolous lichen in the family Psilolechiaceae. It is widely distributed through the world, where it grows on natural and artificial rocky substrates in the shade, often in sheltered underhangs. It forms a ...

'' (Ach.) M.Choisy (1949) – widespread *''

Psilolechia purpurascens ''Psilolechia'' is a genus of four species of crustose lichens. It is the only member of Psilolechiaceae, a family that was created in 2014 to contain this genus. Taxonomy The genus ''Psilolechia'' was established by Abramo Bartolommeo Massalong ...

'' Coppins & Purvis (1987) –

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 ...

''Psilolechia'' species grow in locations that are humid and shaded. ''P. leprosa'' tends to grow on mineral-enriched rocks and

siliceous Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and abundant ...

rocks, and is often recorded around old mines.

References

{{Taxonbar, from1=Q7256032, from2=Q28872150 Lecanorales Lichen genera Lecanorales genera Taxa named by Abramo Bartolommeo Massalongo Taxa described in 1860