Fungalpedia – Note 1368, Asteromidium

 

Asteromidium. Speg.

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1

Classification: Incertae sedis, Incertae sedis, Incertae sedis, Incertae sedis, Pezizomycotina, Ascomycota, Fungi

 

Parasitic and pathogenic on host plants. The sexual morph is undetermined. The asexual morph is characterised by immersed acervulus conidiomata, which are dark brown, scattered to gregarious, pulvinate to doliiform, unilocular, globose and glabrous. The conidiomatal wall is comprised of textura angularis, thin-walled, hyaline to pale brown cells in the basal of the wall. The separate cells scattered in mucilaginous matrix formation on the wall. The conidiophores are reduced to conidiogenous cells. Conidiogenous cells are holoblastic, scattered, indeterminate, cylindrical, hyaline, smooth-walled, with 1–2 sympodial proliferations, scars unthickened, flat, and formed from the basal and lateral of the conidia walls. Conidia are hyaline, thin and smooth-walled, fusiform to cylindrical, gently tapered towards each end, with apex obtuse, with truncate base, three septate and eguttulate (Spegazzini 1888, Sutton 1980, Li et al. 2020).

Notes: Asteromidium was introduced by Spegazzini (1888) based on A. imperspicuum as the type species. In 1884, Saccardo considered Asteromidium as a subgeneric taxon of Actinonema including A. guepinii and A. uvariae (Saccardo 1884). However, Spegazzini (1888) introduced Asteromidium as a generic name, excluding these two species. Petrak and Sydow (1936) provided a detailed description of Asteromidium and acknowledged it as a genus. Sutton (1980) revised this genus and provided a detailed description and accepted A. imperspicuum and A. secundum. Currently, there are only four species listed in Asteromidium in MycoBank (May 2024). There is no sequence data available for Asteromidium in GenBank (May 2024). The updated taxonomic treatment of this genus is Mycosphaerellaceae, incertae sedis (Wijayawardene et al. 2022, Hyde et al. 2024).

 

Type species: Asteromidium imperspicuum Speg., Anal. Soc. cient. argent. 26(1): 66 (1888).

 

image

 

Figure 1 – Asteromidium imperspicuum (redrawn from Sutton 1980) a Conidia. b Vertical section of conidioma. c Conidiogenous cells and developing conidia. Scale bars: a = 20 μm, b = 100 μm, c = 100 μm. (Originally published in Li et al. (2020) and republished with authority).

 

References

Saccardo PA. 1884 – Sylloge Fungorum 3, 1–860.

Spegazzini C. 1888 – Fungi Guarinitici. Pugillus II. Anales de la Sociedad Científica Argentina 26, 5–74.

Hyde KD, Noordeloos MT, Thiyagaraja V, He MQ et al. 2024 – The 2024 Outline of Fungi and fungus-like taxa. Mycosphere 15(1), 5146–6239.

Petrak F, Sydow H. 1936 – Kritisch-systematische Originaluntersuchungen über Pyrenomyzeten, Sphaeropsideen und Melanconieen. VII. Annales Mycologici 34, 11–52.

Li WJ, McKenzie EH, Liu JK, Bhat DJ et al. 2020 – Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100, 279–801.

Sutton BC. 1980 – The Coelomycetes. Fungi imperfecti with pycnidia, acervuli and stromata. Commonwealth Mycological Institute, Kew.

Wijayawardene NN, Hyde KD, Dai DQ, Sánchez-García ML et al. 2022 – Outline of Fungi and fungus-like taxa–2021. Mycosphere 13(1), 53–453.

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