''Heterodermia rubrotricha'' is a

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 ...

species in the family

Physciaceae The Physciaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. A 2016 estimate placed 19 genera and 601 species in the family. Description The Physiaceae family includes various ...

. It is found in Sri Lanka.

Taxonomy

''Heterodermia rubrotricha'' was

formally described A species description is a formal scientific description of a newly encountered species, typically articulated through a scientific publication. Its purpose is to provide a clear description of a new species of organism and explain how it differ ...

Gothamie Weerakoon Gothamie Weerakoon () is a Sri Lankan-based botanist, lichenologist and environmentalist. Early life and education Weerakoon's passion for the environment was initiated during her childhood, which she spent largely outdoors, inspired by her co ...

and

André Aptroot André Aptroot ( Heemskerk, 1961) is a Dutch mycologist and lichenologist. His primary research focus is on biodiversity, particularly tropical lichens, encompassing systematics, floristic surveys, and taxonomic reviews. A prolific research ...

in their 2013 study of lichen

biodiversity Biodiversity is the variability of life, life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and Phylogenetics, phylogenetic diversity. Diversity is not distribut ...

in Sri Lanka. The species is closely related to '' Heterodermia boryi'', sharing a similar configuration, but differs distinctly by having red pigmentation on its marginal . Another related species, '' Heterodermia vulgaris'', also exhibits red pigmentation, but in that species, the pigment occurs over the entire lower surface rather than just the cilia. The

species epithet Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In Taxonomy (biology), taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany) ...

''rubrotricha'' is derived from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

, referring to the red coloration of its cilia.

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 ...

of ''Heterodermia rubrotricha'' is

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 ...

and can form tufts up to 10 cm in diameter. It features whitish lobes that grow linearly, ascending or becoming , reaching lengths up to 4 cm and widths of 0.9–1.6 mm. The lobes taper at the tips, where they are narrower (approximately 0.4 mm wide) and recurved. Branching is , occurring every 0.5–2.0 cm. The upper surface of the lobes is smooth, shiny, and ranges from flat to convex, while the lower surface lacks both a and

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, being instead (cobweb-like) and whitish with corticate margins. A distinguishing characteristic of this species is the presence of prominent, black marginal , which are or branched, dull, 0.1–0.2 mm thick, and can grow up to 8 mm long. These cilia are mostly covered with a containing dark red pigment, excluding the very tips and bases. The species does not produce rhizines, soredia, isidia, or

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 ...

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 ...

(fruiting bodies) are common, measuring 4–7 mm in diameter and occurring (on the surface of the lobes). Their margins feature 6–15 tapering lobes similar in form to the primary lobes. The apothecial are brownish-grey, typically heavily covered with white pruina. The

hymenium The hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in oth ...

(fertile tissue) is 100–180

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 ...

tall, while the (supporting tissue below the hymenium) is pale brown and about 30 μm thick. are brown, contain one septum, have few , and measure 35–43 by 19–22 μm. Chemically, the cortex of ''H. rubrotricha'' reacts yellow with potassium hydroxide (K+), the

medulla Medulla (Latin for "marrow") or medullary may refer to: Science * Medulla oblongata, a part of the brain stem * Renal medulla, a part of the kidney * Adrenal medulla, a part of the adrenal gland * Medulla of ovary, a stroma in the center of the ...

faintly yellow, and the red pigment on the cilia produces a purple reaction.

Thin-layer chromatography Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the sta ...

has identified

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, ...

(in the cortex),

zeorin Zeorin is a triterpene with the molecular formula C30H52O2 which occurs in many lichens A lichen ( , ) is a hybrid colony (biology), colony of algae or cyanobacteria living symbiotically among hypha, filaments of multiple fungus species, al ...

(in the medulla), and a red

anthraquinone Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic hydrocarbon, aromatic organic compound with formula . Several isomers exist but these terms usually refer to 9,10-anthraquinone (IUPAC: 9,10-dioxoanthracene) wherein th ...

pigment on the cilia.

Habitat and distribution

''Heterodermia rubrotricha'' has been found exclusively in Sri Lanka, specifically in the Central Province near

Nuwara Eliya Nuwara Eliya ( ; ) is a city in the hill country of the Central Province, Sri Lanka. Its name means "city on the plain (table land)" or "city of light". The city is the administrative capital of Nuwara Eliya District, with a picturesque landsc ...

, growing on the smooth bark of tea plants (''

Camellia sinensis ''Camellia sinensis'' is a species of evergreen shrub or small tree in the flowering plant family Theaceae. Its leaves, leaf buds, and stems can be used to produce tea. Common names include tea plant, tea shrub, and tea tree (unrelated to ''Me ...

''). It was first collected from a

tea plantation Tea is an aromatic beverage prepared by pouring hot or boiling water over cured or fresh leaves of ''Camellia sinensis'', an evergreen shrub native to East Asia which probably originated in the borderlands of south-western China and northe ...

at an elevation of about . The genus ''

Heterodermia ''Heterodermia'' is a genus of lichenized fungi in the family Physciaceae. The genus has a widespread distribution, especially in tropical regions, and contains about 80 species. Description ''Heterodermia'' are subterranean or almost upright le ...

'' is generally species-rich in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

mountainous regions, and Sri Lanka is known for its diverse assemblage of foliose lichens, with ''Heterodermia'' potentially being the most species-rich foliose genus in the region. At the time of its original publication, ''H. rubrotricha'' was known only from its type locality.

References

{{Taxonbar, from=Q107740019 Caliciales Lichen species Lichens described in 2013 Taxa named by André Aptroot Taxa named by Gothamie Weerakoon