Fungalpedia – Note 803, Microthecium
Microthecium Corda
Citation when using this data: Huang SK et al. 2021 (in prep.) – Fungalpedia, Ascomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig. 1l
Classification: Ceratostomataceae, Melanosporales, Hypocreomycetidae, Sordariomycetes, Pezizomycotina, Ascomycota, Fungi
Saprobic on wood or leaves or isolated from soil, sometimes fungicolous. Sexual morph: Ascomata perithecial or without an external opening, superficial or immersed, globose to subglobose, scattered or gregarious, yellowish to brown, membranaceous, translucent, glabrous, tomentose or hairy, necks short or absent, with or lacking ostioles. Peridium usually translucent or semi-translucent, membranaceous, composed of yellow to pale brown cells of textura angularis. Asci 4- or 8-spored, clavate to pyriform, evanescent. Ascospores irregular or bi-seriate, hyaline becoming brown to black, ellipsoidal to citriform, usually umbonate and truncate at both ends, smooth-walled or verrucose or with reticulate ribs on surface, with a germ pore at each end, mostly with guttules. Sexual morph: Conidiophores unbranched or branched, cylindrical, septate. Conidia subglobose to oval, hyaline to pale brown, smooth-walled. Bulbils globose to ellipsoidal, pale brown to reddish brown (adapted from Udagawa & Cain 1969, Marin-Felix et al. 2018).
Notes – Microthecium was introduced by Corda (1842) and typified by M. zobelii which was found growing in the hymenial tissue of Rhizopogon albus. This genus has translucent ascomata and ellipsoidal to citriform ascospores with umbonate and truncated ends, simliar to Melanospora and Sphaerodes (Winter 1887b, Cannon & Hawksworth 1982). Therefore, Microthecium was regarded as a synonym of Melanospora, until Marin-Felix et al. (2018) sequenced several species in these two genera, and Microthecium species existed in Ceratostomataceae as a clade independent of Melanospora. Thus, Microthecium was re-accepted as a genus in Ceratostomataceae (Hyde et al. 2020e, Wijayawardene et al. 2020). In this study, Microthecium species clustered (86%ML/0.92BY) and are basal to Harzia and Melanospora (57%ML/1.00BY) in Ceratostomataceae.
Type species: Microthecium zobelii Corda, Icon. fung. (Prague) 5: 74 (1842).
Other accepted species: Species Fungorum – search Microthecium.
Figure 1 – Melanospora theleboloides: a–d (G-326774/1-G00127866, holotype). a Material. b Crushed ascomata. c Immature asci. d ascospores; Pustulipora corticola: e–f (redrawn from Cannon 1982). e Ascus. f Ascospores; Erythrocarpon microstomum: g–k (redrawn from Zukal 1885). g Ascoma cross section. h Ascus. i Ascospores. j–k Two types of conidiophores with conidia; Microthecium zobelii: l (redrawn from Corda 1842, Udagawa & Cain 1969). l Ascospores. Microthecium foveolatum: m–n (redrawn from Hawksworth & Udagawa 1977). m Ascospores with irregular ridges. n Conidiophores with conidia. Scale bars: g = 200 µm, b = 100 µm, e, k = 50 µm, c–d, f, h, j, l = 20 µm, i, m–n = 10 µm.
References
Corda ACJ. 1842 – Icones fungorum hucusque cognitorum. Prague 5, 1–92.
Hawksworth DL, Udagawa S. 1977 – Contributions to a monograph of Microthecium. Transactions of the Mycological Society of Japan 18, 143–154.
Winter G. 1887b – Die Pilze, II. Ascomyceten. In Rabenhorst’s Kryptogamenflora von Deutschland, Oesterreich und der Schweiz 1(2), 1–928.
Zukal H. 1885 – Ueber einige neue Pilze, Myxomyceten und Bakterien. Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 35, 333–342.
Entry by
Shi-Ke Huang, State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Guiyang 550025, China, The Engineering Research Center of Southwest Bio-Pharmaceutical Resources, Ministry of Education, Guizhou University, Guiyang 550025, Guizhou Province, China, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand, School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand, The Mushroom Research Centre, Guizhou University, Guiyang 550025, China
Published online 14 September 2021