Arachnomyces flavidulus
{{Short description|Species of ascomycete fungus}}
{{Italic title}}
{{Speciesbox
|taxon=Arachnomyces flavidulus
|authority=Speg. 1912
}}
Arachnomyces flavidulus is a species of ascomycete fungus discovered in 1912 by botanist Carlo Luigi Spegazzini.{{cite journal|date=2014|journal=ProBiota: Serie Documentos|issue=34|title=Guía alfabética de especies de hongos publicadas por Carlos Luis Spegazzini|last1=Perla|issn=1666-731X|editor-last1=López|editor-first1=Hugo Luis|editor-last2=Ponte Gómez|editor-first2=Justina|first1=Hugo O.|publisher=Universidad Nacional de La Plata|url=http://sedici.unlp.edu.ar/handle/10915/44037}} It was recovered from rotting Eucalyptus globulus leaves from a park in Buenos Aires, Argentina.{{cite book|title=Anales del Museo Nacional de Historia Natural de Buenos Aires|date=29 April 1912|publisher=Impr. y Casa Editora "Juan A. Alsina"|pages=25|archive-url=https://web.archive.org/web/20220907205924/https://www.biodiversitylibrary.org/bibliography/5597|archive-date=2022-09-07|url=https://www.biodiversitylibrary.org/bibliography/5597|access-date=2022-09-07|volume=XXIII|publication-place=Buenos Aires|first1=Carolo|last1=Spegazzini|chapter=Mycetes argentinenses|url-status=live}}
Morphology
The fungus has a sparse, superficial, sulphurous matrix surrounding its surface. Attached to the fruiting body is a subiculum (wool-like mycelium growth),{{cite web|url=https://fungiforthepeople.org/mushroom-info/mycoglossary/|title=Myco Glossary: a glossary of mycological terms|website=WordPress|author=Fungi For The People|access-date=2022-09-08|quote=SUBICULUM – a wool- or crust-like growth of mycelium under fruit bodies.}} very thin and loose, formed by irregularly branched slender hyphae (1.5-2 μm). The perithecia 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 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.{{cite book|title=Sylloge Fungorum omnium hucusque cognitorum|volume=XXIV Sectio I Supplementum universale Pars X. Phycomycetae, Laboulbeniomycetae Pyrenomycetae p. p.|date=15 July 1926|publication-place=Abellinum|editor-last1=Trotter|editor-first1=Alessandro|editor-last3=Saccardo|editor-first3=Domenico|editor-last2=Traverso|editor-first2=Giovanni Battista|author=P. A. Saccardo|url=https://bibdigital.rjb.csic.es/records/item/13451-sylloge-fungorum-vol-xxiv-sectio-i?offset=1|publisher=Sumptibus Coheredum Saccardo. Typis Pergola, Vendit extra Italiam R. Friedländer & Sohn, Berolini}} The species appears similar to Eurotium.
Taxonomy
A. flavidulus was listed as a doubtful species since 1970 because it produces ascospores that differ from other Arachnomyces members.{{cite journal|first1=BING-DA|last1=SUN|first2=YU-GUANG|last2=ZHOU|first3=AMANDA-JUAN|last3=CHEN|first4=JOS|last4=HOUBRAKEN|title=Phylogeny and a new species of the genus Arachnomyces (Arachnomycetaceae)|journal=Phytotaxa|volume=394|issue=1|date=2019|pages=089–097|doi=10.11646/phytotaxa.394.1.6|url=https://www.researchgate.net/profile/Amanda-Chen-2/publication/331328914_Phylogeny_and_a_new_species_of_the_genus_Arachnomyces_Arachnomycetaceae/links/5cbe7aa24585156cd7ab5c1b/Phylogeny-and-a-new-species-of-the-genus-Arachnomyces-Arachnomycetaceae.pdf}}