''Hypotrachyna aspera'' 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 ...

. It occurs in the mountains of

Minas Gerais Minas Gerais () is one of the 27 federative units of Brazil, being the fourth largest state by area and the second largest in number of inhabitants with a population of 20,539,989 according to the 2022 Brazilian census, 2022 census. Located in ...

and Paraná, where it grows on tree bark in humid forests at an elevation of about . This small lichen forms loose, ragged rosettes 4–6 cm across with very narrow that give it a finely frilled appearance, and it reproduces through blister-like that burst to release powdery

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 ...

Taxonomy

''Hypotrachyna aspera'' was formally described in 2002 by Célio H. Ribeiro and Marcelo Marcelli during their survey of the mountainous Atlantic Forest–

cerrado The Cerrado () is a vast ecoregion of Tropics, tropical savanna in central Brazil, being present in the states of Goiás, Mato Grosso do Sul, Mato Grosso, Tocantins, Maranhão, Piauí, Bahia, Minas Gerais, São Paulo (state), São Paulo, Paraná ...

mosaic in south-eastern Brazil. The authors placed it in the large parmelioid family

, within the genus ''

Hypotrachyna ''Hypotrachyna'' is a genus of lichenized fungi within the family Parmeliaceae. According to the ''Dictionary of the Fungi'' (10th edition, 2008), the widespread genus contains about 198 species. ''Hypotrachyna'' was circumscribed by American lic ...

''—a group characterised by

foliose 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 lichen growth forms, growth forms of lichens. It typically has distinct upper and lo ...

(leaf-like) thalli with a black lower and diverse

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

s. The

type specimen In biology, a type is a particular wikt:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally associated. In other words, a type is an example that serves to ancho ...

was collected on quartzitic rock at the margin of the Tanque Grande reservoir in the Serra do Caraça,

, about 1100 m elevation. Chemically the species is distinguished by the presence of atranorin in the cortex and alectoronic acid in the medulla, a combination otherwise uncommon in the genus. These substances, together with the non-reactive (UV–) cortex and the medullary K+ (

rose A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...

) reaction, helped the original authors delimit the taxon from similar species such as '' H. brueggeri'' and '' H. dactylifera''.

Description

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 ...

forms loose, rather ragged rosettes 4–6 cm across. Its upper surface is a dull white that may weather to pale grey; individual lobes (laciniae) are very narrow—only 1.0–2.5 mm wide—giving the thallus a finely frilled appearance. These lobes are more or less flat to slightly up-turned, have truncate (squared-off) tips and carry a thin black marginal line that accentuates each division. , blister-like swellings that rise from the surface, develop mainly near the lobe edges; they soon burst to release a coarse, grainy powder of

(minute balls of algal and fungal cells used for

vegetative reproduction Vegetative reproduction (also known as vegetative propagation, vegetative multiplication or cloning) is a form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or specializ ...

). Unlike the closely related species mentioned above, the pustules here lack any K-reactive yellow pigment, remaining whitish even after reagent is applied. Internally, the medulla (the loose cottony layer inside the thallus) is white, reacting K+ (rose) because of alectoronic acid. The lower surface is jet black, shiny and wrinkled toward the centre but becomes chestnut brown near the margin. Attachment to the

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 (aquatic environment), the earthy material that exi ...

is achieved by numerous forked

rhizine In lichens, rhizines are multicellular root-like structures arising mainly from the lower surface. A lichen with rhizines is termed rhizinate, while a lichen lacking rhizines is termed erhizinate. Rhizines serve only to anchor the lichen to their s ...

s—root-like fibres—0.3–0.8 mm long that are the same colour as the lower cortex. No

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 ...

( sexual fruit-bodies) were seen, and

pycnidia A pycnidium (plural pycnidia) is an asexual fruiting body produced by mitosporic fungi, for instance in the order Sphaeropsidales ( Deuteromycota, Coelomycetes) or order Pleosporales (Ascomycota, Dothideomycetes). It is often spherical or inve ...

(minute flask-shaped

asexual Asexual or Asexuals may refer to: *Asexual reproduction **Asexual reproduction in starfish *Asexuality, the lack of sexual attraction to anyone or lack of interest in or desire for sexual activity. **Gray asexuality, the spectrum between asexualit ...

organs) were likewise absent in the type series.

Habitat and distribution

''Hypotrachyna aspera'' is known to occur only in the Serra do Caraça massif (Minas Gerais) in south-eastern Brazil. All material was collected between 1100 and 1150 m on acid

siliceous rock Siliceous rocks are sedimentary rocks that have silica (SiO2) as the principal constituent. The most common siliceous rock is chert; other types include diatomite. They commonly form from silica-secreting organisms such as radiolarians, diatoms, o ...

bordering the Tanque Grande reservoir—a setting where moist

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures lapse rate, fall as elevation increases, causing the ecosystem to stratify. This stratification is ...

forest intergrades with open

candeia Antônio Candeia Filho better known as Candeia (August 17, 1935 – November 16, 1978) was a Brazilian samba singer, songwriter, and musician. Early life Born in Rio de Janeiro to Antonio Candeio and Dona Maria, Antonio was a renowned flautist ...

(''Eremanthus erythropappus'') woodland. Here the lichen grows in partially shaded, rain-washed situations where fog is frequent and the air remains humid for much of the year. Because it has been reported solely from this restricted area despite extensive collecting in adjacent ranges, the species may be either genuinely localised or easily overlooked owing to its small size and rather nondescript whitish thallus. Further fieldwork in the Espinhaço and Mantiqueira highlands will be needed to determine its full geographic range.

References

{{Taxonbar, from=Q10530451

aspera Aspera may refer to: Music * Aspera (band), an American indie rock band * ''(a)spera'', a 2009 album by Mirah * Above Symmetry, a Norwegian progressive metal band originally known as Aspera * "Aspera", the lead track from ''We Will Become Like Bir ...

Lichen species Lichens described in 2002 Lichens of Brazil