Fungalpedia – Note 703, Viegasella
Viegasella Inácio & P.F. Cannon.
Citation when using this data: D. S. Marasinghe et al. 2023 (in prep.) – Fungalpedia, Ascomycota.
Index Fungorum, Facesoffungi, MycoBank, GenBank., Fig 1
Classification: Parmulariaceae, Asterinales, Dothideomycetidae, Dothideomycetes, Pezizomycotina, Ascomycota, Fungi
Epiphytic and parasitic on leaf surface. Superficial hyphae absent. Stromata solitary to scattered, sometimes confluent, variable in shape, circular to irregular, radiating locules from the central, opening by longitudinal slit, light brown to reddish with a diffuse edge. Sexual morph: Ascostromata superficial, black, shiny, appearing as flexuous lines on the leaf surface, opening by longitudinal slits. Ostiole conspicuous. Peridium thick at the sides, composed of brown to black thick-walled cells of textura angularis, outer brown to black carbonaceous substance and internal hyaline cells, 2-layered. Upper and lower wall thin, not well developed, sometimes absent. Hamathecium composed of cellular, septate, hyaline, branched, pseudoparaphyses, verrucose at the tips. Asci 8-spored, bitunicate, cylindrical to clavate, short-pedicellate, thin-walled, embedded in mucilage. Ascospores biseriate or multiseriate, ellipsoid to fusiform or ellipsoid to narrowly ovoid, hyaline to pale brown, normally unequally 1-septum, verrucose, constricted at each transverse septum, upper cell wider, lower cell narrows and longer, guttulate, thin gelatinous sheath present or absent (Adapted from Inácio and Cannon 2003; Tian et al. 2016). Asexual morph: Undetermined.
Notes: Inácio and Cannon (2003) established Viegasella with the type species Viegasella pulchella. Viegasella is characterized by having a circular, elliptical or irregular ascostromata with radiating locules opening by longitudinal slits, cylindric-clavate 8-spored asci with pale to mid brown, cylindricellipsoidal, 1-septum ascospores The asexual morph of V. pulchella has not been reported. It is morphologically similar to Aldonata pterocarpi in having a circular to irregular ascostromata with radially arranged ridges with greyish-white to light brown margin surrounding the colony (Inácio and Cannon 2003). However, Viegasella pulchella has tiny black spots around greyish-white colonies and 1-septum ascospores, while Aldonata pterocarpi has the tiny black conidiomata at center of leaf spots and muriform, caudiform ascospores (Tian et al. 2016). Inácio and Cannon (2003) observed intracellular coralloid haustoria with brown pegs in internal stroma and external hyphae were not observed.
Type species Viegasella pulchella (Speg.) Inácio & P.F. Cannon, Mycol. Res. 107(1): 83 (2003)
≡ Parmularia pulchella (Speg.) Sacc. & P. Syd., Syll. fung. (Abellini) 14(2): 709 (1899)
≡ Schneepia pulchella Speg., Anal. Soc. cient. argent. 26(1): 55 (1888)
Other accepted species: species Fungorum – search Viegasella.
Figure 1 – Viegasella pulchella. a Ascostromata on the host. b Ascus. c Vertical transverse section showing coralloid haustoria (red arrows). d Ascospores. Scale bars: a = 200 µm, b = 10 µm, c = 20 µm, d = 5 µm. Redrawn from Tian et al. (2016) and Inácio and Cannon (2003)
References
Entry by
Diana Sandamali Marasinghe, 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, Mushroom Research Foundation, 128 M.3 Ban Pa Deng T. Pa Pae, A. Mae Taeng, Chiang Mai, 50150, Thailand
Published online 29 August 2023