''Arachnomyces flavidulus'' is a species of

ascomycete Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defi ...

fungus discovered in 1912 by

botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...

Carlo Luigi Spegazzini Carlo Luigi Spegazzini, in Spanish Carlos Luis Spegazzini (20 April 1858 – 1 July 1926), was an Italian-born Argentinian botanist and mycologist. On the 1881/1882 expedition led by Giacomo Bove to explore Patagonia and Tierra del Fuego, th ...

. It was recovered from rotting ''

Eucalyptus globulus ''Eucalyptus globulus'', commonly known as southern blue gum or blue gum, is a species of tall, evergreen tree endemic to southeastern Australia. This ''Eucalyptus'' species has mostly smooth bark, juvenile leaves that are whitish and waxy on ...

'' leaves from a park in

Buenos Aires Buenos Aires ( or ; ), officially the Autonomous City of Buenos Aires ( es, link=no, Ciudad Autónoma de Buenos Aires), is the capital and primate city of Argentina. The city is located on the western shore of the Río de la Plata, on South ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

Morphology

The fungus has a sparse, superficial, sulphurous matrix surrounding its surface. Attached to the fruiting body is a subiculum (wool-like mycelium growth), very thin and loose, formed by irregularly branched slender

hyphae 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 ...

(1.5-2 μm). The

perithecia 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 ...

are scattered, globose or globose-depressed, 250-500 μm in diameter, lacking an opening or ostiole, of yellow color, fragile, densely covered in yellowish brittle hairs of thinly membranous indistinct composition. The

asci ASCI or Asci may refer to: * Advertising Standards Council of India * Asci, the plural of ascus, in fungal anatomy * Accelerated Strategic Computing Initiative * American Society for Clinical Investigation * Argus Sour Crude Index * Association of ...

are subglobose, tiny, clustered, measuring 12 μm in diameter, with rapidly flowing octospores. These spores are globose to ellipsoid in shape, very thinly coated and light, 4 to 3 μm wide. The species appears similar to ''

Eurotium ''Eurotium'' is a genus of fungi belonging to the family Trichocomaceae The Trichocomaceae are a family of fungi in the order Eurotiales. Taxa are saprobes with aggressive colonization strategies, adaptable to extreme environmental condition ...

''.

Taxonomy

''A. flavidulus'' was listed as a doubtful species since 1970 because it produces

ascospores 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 or ...

that differ from other ''

Arachnomyces ''Arachnomyces'' is a genus of cleistothecial ascomycete fungi described in 1902, of which the anamorph (asexual) stage is the genus ''Onychocola''. Although morphologically similar to members of other families, the fungus now belongs to its o ...

'' members.

References

{{taxonbar, from=Q107487918 Fungi described in 1912 Fungi of Argentina Eurotiomycetes