''Byssoloma brunneodiscum'' is a species of foliicolous (leaf-dwelling)

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.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 ...

. Found in China, it was formally described as a new species in 2020 by Wei-Cheng Wang and Jiang-Chun Wei. The

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

was collected by Wang in the Mingfeng Valley of Jianfeng Ridge (

Ledong County Ledong Li Autonomous County (; postal: Loktung) is an autonomous county in Hainan province, China. It is one of six autonomous counties of Hainan. Its postal code is 572500, and in 1999 its population was 468,834 people, largely made up of the Li ...

Hainan Hainan (, ; ) is the smallest and southernmost province of the People's Republic of China (PRC), consisting of various islands in the South China Sea. , the largest and most populous island in China,The island of Taiwan, which is slightly l ...

) at an altitude of . It is only known to occur at high-altitude

rainforest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainfores ...

s on Hainan Island, where it grows sparsely on leaf surfaces in the damp

understorey In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...

. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''brunneodiscum'' refers to the brown discs that are characteristic of the

apothecia An ascocarp, or ascoma (), 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. Ascocarps are mo ...

of this species. The lichen makes 2,5,7-trichloro-3-''O''-methylnorlichexanthone, a secondary chemical that is detectable using

thin-layer chromatography Thin-layer chromatography (TLC) is a chromatography technique used to separate non-volatile mixtures. Thin-layer chromatography is performed on a sheet of an inert substrate such as glass, plastic, or aluminium foil, which is coated with a t ...

. '' Byssoloma annuum'' is similar in appearance and chemistry, but is distinguished from ''B. brunneodiscum'' by its orange-yellow apothecia and colourless hypothecium.

References

Pilocarpaceae Lichen species Lichens described in 2020 Lichens of China {{Lecanorales-stub