''Amethicium'' is a fungal

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

in the family

Phanerochaetaceae The Phanerochaetaceae are a family of mostly crust fungi in the order Polyporales. Taxonomy Phanerochaetaceae was first conceived by Swedish mycologist John Eriksson in 1958 as the subfamily Phanerochaetoideae of the Corticiaceae. It was later ...

. A

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus, it contains the single species ''Amethicium rimosum'', a

crust fungus The corticioid fungi are a group of fungi in the Basidiomycota typically having effused, smooth basidiocarps (fruit bodies) that are formed on the undersides of dead tree trunks or branches. They are sometimes colloquially called crust fungi or pa ...

first reported from

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...

in 1983. ''Amethicium'' is primarily characterized by its purple

fruit body In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the Ovary (plants), ovary after flowering plant, flowering. Fruits are the means by which flowering plants (also known as angiosperms) disseminate their ...

and a dimitic

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 or ...

l system (two types of hyphae: generative and skeletal). The felt-like tissue layer covering the substrate (the subiculum) comprises a thin layer of densely intertwined skeletal hyphae.

Taxonomy

''Amethicium rimosum'' was described scientifically by Swedish mycologist Kurt Hjortstam in 1983, based on collections made by

Leif Ryvarden Leif Randulff Ryvarden (born 9 August 1935) is a Norwegian mycologist. Early life and education Leif Ryvarden was born in Bergen as a son of Einar Norberg Johansen (1900–1959) and Hjørdis Randulff (1912–1975). He finished his secondary edu ...

a decade earlier. The type locality was on the southern slopes of

Mount Kilimanjaro Mount Kilimanjaro () is a dormant volcano in Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest mountain in Africa and the highest free-standing mountain above sea level in the world: above sea level and ab ...

, at an elevation between . There have been a few species formerly classified in the ''Amethicium'' that have since been transferred to other genera. ''Amethicium chrysocreas'' (Berk. & M.A. Curtis) Sheng H. Wu 1990, and ''Amethicium leoninum'' (Burds. & Nakasone) Sheng H. Wu 1990, are now in '' Crustodontia'' and ''

Hyphoderma ''Hyphoderma'' is a genus of crust fungi in the family Meruliaceae. It was circumscribed by German botanist Karl Friedrich Wilhelm Wallroth in 1833. Species , Index Fungorum ''Index Fungorum'' is an international project to index all formal ...

'', respectively. ''Amethicium luteoincrustatum'' Hjortstam & Ryvarden 1986 is now classified as a member of '' Cericium''.

Description

Fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

of ''Amethicium rimosum'' form soft, thin (about 200–300

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 Unit ...

thick) smooth crust that is closely attached to the surface of its substrate. Its colour is initially bluish or purplish, but tends to become greyish with less pronounced bluish tints in age. The

l system is dimitic, meaning that it contains both generative hyphae and skeletal hyphae. The highly-branched, intertwined basal hyphae—reminiscent of the morphologically similar binding hyphae—form a dense tissue. They are thin to moderately thick-walled, simple

septate In biology, a septum (Latin for ''something that encloses''; plural septa) is a wall, dividing a cavity or structure into smaller ones. A cavity or structure divided in this way may be referred to as septate. Examples Human anatomy * Interatri ...

, and indextrinoid. Subhymenial hyphae (found in the tissue layer beneath 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 others some ...

) are densely arranged, short-celled, thin-walled, and have

clamp connection A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of Basidiomycetes fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

Cystidia A cystidium (plural cystidia) is a relatively large cell found on the sporocarp of a basidiomycete (for example, on the surface of a mushroom gill), often between clusters of basidia. Since cystidia have highly varied and distinct shapes that ar ...

are absent from the hymenium.

Basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

are terminal, roughly club shaped, fairly small (25 by 4–4.5 µm), and have four

sterigmata In biology, a sterigma (pl. sterigmata) is a small supporting structure. It commonly refers to an extension of the basidium (the spore-bearing cells) consisting of a basal filamentous part and a slender projection which carries a spore at the ti ...

Spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

are thin-walled, smooth, and

hyaline A hyaline substance is one with a glassy appearance. The word is derived from el, ὑάλινος, translit=hyálinos, lit=transparent, and el, ὕαλος, translit=hýalos, lit=crystal, glass, label=none. Histopathology Hyaline cartilage is ...

(translucent). The spores, which are both

inamyloid In mycology a tissue or feature is said to be amyloid if it has a positive amyloid reaction when subjected to a crude chemical test using iodine as an ingredient of either Melzer's reagent or Lugol's solution, producing a blue to blue-black stain ...

and indextrinoid, have dimensions of 3.5–4 by 1.75–2 µm.

References

{{Taxonbar, from=Q4745927 Fungi of Africa Phanerochaetaceae Monotypic Polyporales genera Fungi described in 1983