Chaetomium Kunze, Mykologische Hefte (Leipzig) 1: 15 (1817)
Sordariomycetidae, Sordariales, Chaetomiaceae, Chaetomium
Parasitic or saprobic on plant remains, straw, seeds, dung, feathers of birds, soil, paper, textiles and humans. Sexual morph: Ascomata dark, olive brown to greyish yellow, grey or green, superficial, globose, subglobose to ovoid, pyriform or ampulliform, numerous, with broadly curved base and narrow ostiole. Peridium with thick wall, composed of several layers of pale brown cells of textura intricata or textura epidermoidea. Ascomata brown, hairs numerous, usually unbranched, flexuous, undulate or coiled, often tapering, septate, broad at the base. Asci 8-spored, rarely 4-spored, unitunicate, clavate, obovate, fusiform, or nearly cylindrical, pedicellate, apically rounded, evanescent. Ascospores hyaline when young, later brown, overlapping biseriate to packed, variable in shape, most are ellipsoidal, broadly fusiform or limoniform, aseptate, thick and smooth-walled, containing several small guttules, with an apical germ pore. Asexual morph: Hyphomycetous. Colonies brown or orange or white, woolly, border even, reverse buff- colored to brown, aerial mycelium cottony or felty, with funiculose setae and hyphae. Mycelium abundant, intra-matrical and aerial, composed of hyaline or dark brown, septate, hyphae. Conidiophores reduced to conidiogenous cells or simple vegetative hyphae, branched, hyaline, septate, with smooth or slightly rough wall. Conidiogenous cells hyaline, lateral or intercalary on aerial mycelium, or immersed in agar or on conidiophore, phialidic. Conidia hyaline to brown, subglobose to globose, or oblong, occasionally cylindrical to pyriform, formed solitary or in chains, aseptate, smooth-walled, wall thickens with age (adapted from Maharachchikumbura et al. 2016).
Type species: Chaetomium globosum Kunze, Mykologische Hefte (Leipzig) 1: 16 (1817)
Notes: Chaetomium is the largest genus in Chaetomiaceae. The genus was reviewed by Maharachchikumbura et al. (2016) and Wang et al. (2016a, b, 2019). The genera Bommerella, Chaetomidium and Chaetomiopsis were proposed as synonyms of Chaetomium (Moustafa & Abdul-Wahid 1990, Doveri 2008, Wang et al. 2016a, b, 2019). Chaetomium contains more than 150 species (Wijayawardene et al. 2017); they grow on soil and decaying twigs (Wang et al. 2016a, b, Zhang et al. 2017). Wang et al. (2016a, b, 2019) described novel Chaetomiaceae taxa collected from indoor environments. Many new species, collected from soil, were published by Zhang et al. (2017). The genus is characterised by globose, ellipsoid to ovate or obovate ascomata with or lacking ostioles, hypha-like, flexuous, undulate, coiled to simply or dichotomously branched ascomatal hairs, clavate or fusiform, evanescent asci, and limoniform to globose, bilaterally flattened ascospores. Asexual morphs, if produced, are acremonium-like (Wang et al. 2016a).
Species illustrated in this entry
Chaetomium globosum Kunze
Doveri F. 2008 – “Aggiornamento sul genere Chaetomium con descrizione di alcune specie coprofile, nuove perl” Italia - “An Update on the Genus Chaetomium with Descriptions of Some Coprophilous Species, New to Italy.”. Pagine di Micologia 29, 1–60
Maharachchikumbura SSN, Hyde KD, Jones EBG, McKenzie EHC et al. 2016 – Families of Sordariomycetes. Fungal Diversity 79, 1–317
Moustafa AF, Abdul-Wahid OA. 1990 – Chaetomiopsis, a new perithecial ascomycete genus from Egyptian soils. Mycologia 82, 129–131
Wang XW, Houbraken J, Groenewald JZ, Meijer M et al. 2016a – Diversity and taxonomy of Chaetomium and chaetomium-like fungi from indoor environments. Studies in Mycology 84, 145–224
Wang XW, Lombard L, Groenewald JZ, Li J et al. 2016b – Phylogenetic reassessment of the Chaetomium globosum species complex. Persoonia-Molecular Phylogeny and Evolution of Fungi 36, 83–133
Wang XW, Yang FY, Meijer M, Kraak B et al. 2019 – Redefining Humicola sensu stricto and related genera in the Chaetomiaceae. Studies in Mycology 93, 65–153
Wijayawardene NN, Hyde KD, Rajeshkumar KC, Hawksworth DL et al. 2017a – Notes for genera: Ascomycota. Fungal Diversity 86, 1–594
Zhang Y, Wu W, Cai L. 2017 – Polyphasic characterisation of Chaetomium species from soil and compost revealed high number of undescribed species, Fungal Biology 121, 21–43