''Calicium trabinellum'', commonly known as the yellow-collar stubble lichen, is a widespread species of

pin lichen Lichens are composite organisms made up of multiple species: a fungal partner, one or more photosynthetic partners, and sometimes a basidiomycete yeast. They are regularly grouped by their external appearance – a characteristic known as their ...

in the family

Caliciaceae The Caliciaceae are a family of mostly lichen-forming fungi belonging to the class Lecanoromycetes in the division Ascomycota. Although the family has had its classification changed several times throughout its taxonomic history, the use of m ...

. It was first described by Swedish lichenologist

Erik Acharius Erik Acharius (10 October 1757 – 14 August 1819) was a Swedish botanist who pioneered the Taxonomy (biology), taxonomy of lichens and is known as the "father of lichenology." Acharius was famously the last pupil of Carl Linnaeus. Life Ac ...

in 1803 as ''Calicium xylonellum'' ß ''trabinellum''. He made the

new combination ''Combinatio nova'', abbreviated ''comb. nov.'' (sometimes ''n. comb.''), is Latin for "new combination". It is used in taxonomic biology literature when a new name is introduced based on a pre-existing name. The term should not to be confused wi ...

''Calicium trabinellum'' in a later chapter of the same publication. The

thallus Thallus (plural: 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. Many of these organisms ...

of the lichen is usually visible as a stain on the wood upon which it is growing. The

apothecium 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 ...

resembles a small black pin, with a stalk tall, holding a black mound of

ascospore An ascus (; ) is the sexual spore-bearing cell produced in ascomycete fungi. Each ascus usually contains eight ascospores (or octad), produced by meiosis followed, in most species, by a mitotic cell division. However, asci in some genera o ...

s (called a mazaedium). The underside of the mazaedium is dusted with

pruina Pruinescence , or pruinosity, is a "frosted" or dusty-looking coating on top of a surface. It may also be called a pruina (plural: ''pruinae''), from the Latin word for hoarfrost. The adjectival form is pruinose . Entomology In insects, a "blo ...

, which contains the compound

vulpinic acid Vulpinic acid is a natural product first found in and important in the symbiosis underlying the biology of lichens. It is a simple methyl ester derivative of its parent compound, pulvinic acid, and a close relative of pulvinone, both of which d ...

that gives it its yellow colour. The spores of ''Calicium trabinellum'' have roughly textured walls and measure 7–10 by 4–6

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...

. The lichen is common on dead wood in

boreal Boreal may refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernander sequence of northern Europe, during the Holocene epoch *Boreal climate, a climate characterized by long winters and short, cool to mild ...

and

hemiboreal Hemiboreal means halfway between the temperate and subarctic (or boreal) zones. The term is most frequently used in the context of climates and ecosystems. Botany A hemiboreal forest has some characteristics of a boreal forest to the north, and ...

forests. In addition to Europe and North America, ''Calicium trabinellum'' has been recorded from Africa and Asia.

References

trabinellum Lichen species Taxa named by Erik Acharius Lichens described in 1803 Lichens of Africa Lichens of Asia Lichens of Europe Lichens of North America {{Caliciales-stub