Pleosporales » Melanommataceae » Mamillisphaeria

Mamillisphaeria dimorphospora

Mamillisphaeria dimorphospora K.D. Hyde, S.W. Wong & E.B.G. Jones

Index Fungorum number: IF 415619

 

Following description is adapted from Hyde et al. 1996)

 

Sexual morph: Ascomata 455–650 μm high × 980–1430 μm diam., scattered or in small groups, superficial, conical, carbonaceous, papillate, under pseudostroma which forms a thin layer on the host surface, up to 50 μm thick between the ascomata and 125–250 μm thick on the ascomata surface. Peridium 10–25 μm thick, comprising several layers of compressed, densely packed, thin-walled, hyaline cells. A wedge-shaped area of vertically orientated hyaline palisade-like cells occurs at the periphery. Hamathecium of dense, trabeculate pseudoparaphyses, ca. 1 μm broad, hyaline, branching and anastomosing, septate, embedded in mucilage. Two types of asci and ascospores exist in the same ascoma: TYPE 1: asci 185–320 × 40–100 μm (x̄ = 210 × 78μm, n = 50), 8-spored, cylindro-clavate, bitunicate, fissitunicate, short-pedicellate, with an ocular chamber (to 13 μm wide × 5 μm high). Ascospores 66–84 × 20–38 μm (x̄ = 78 × 25μm, n = 50), 2-4-seriate, hyaline, ellipsoidal, constricted at the central septum, with pad-like mucilaginous appendage at each end and with some mucilage associated around the spore, and TYPE 2: asci 158–242 × 8–15 μm (x̄ = 182 × 11μm, n = 50), 8-spored, cylindrical, bitunicate, fissitunicate, pedicellate, with an ocular chamber and faint apical ring, ascospores 29–42 × 6–9 μm (x̄ = 35 × 7μm, n = 50), 1-2-seriate, brown, ellipsoidal-fusoid, surrounded by a thin mucilaginous sheath. Asexual morph: Undetermined. (Description from Zhang et al. 2012).

 

Material examined: BRUNEI, on submerged wood, Aug. 1997, leg. K.D. Hyde (HKU(M) 7425).

 

Freshwater distribution: Australia (Bareen and Iqbal 1994; Hyde et al. 1996; Vijaykrishna and Hyde 2006), Brunei (Ho et al. 2001), Malaysia (Ho et al. 2001)

 

Fig 1. Mamillisphaeria dimorphospora (BRIP 22967a). (g, j Type 1, h, i, k Type 2) a Specimen and herbarium label. b, c Ascomata on host surface with a small papilla. d Vertical section of ascoma. e Structure of peridium. f Trabeculate pseudoparaphyses. g–i Asci. j, k Ascospores. Scale bars: b = 1 mm, c = 500 μm, d = 100 μm, e = 50 μm, f–i = 20 μm, j, k = 10 μm (Dong et al. 2020)

 

Fig 2. Mamillisphaeria dimorphospora (from HKU(M) 7425, paratype?). a Ascomata scattered on the host surface. Note the small papilla, b Section of an ascoma, c, d Asci (TYPE 1), e Trabeculate pseudoparaphyses in a gelatinous matrix, f–j Ascospores. Scale bars: a = 0.5 mm, b–d = 100 μm, e = 10 μm, f–j = 20 μm (Zhang et al. 2012)

 

References

Bareen FE, Iqbal SH (1994) Seasonal occurrence of fresh-water hyphomycetes on submerged fallen leaves in canal waters. Can J Bot 72:1316–1321

Ho WH, Hyde KD, Hodgkiss JI, Yanna (2001) Fungal communities on submerged wood from streams in Brunei, Hong Kong, and Malaysia. Mycol Res 105:1492–1501

Hyde KD, Wong SW, Jones EBG (1996) Tropical Australian freshwater fungi XI. Mamillisphaeria dimorphospora gen. et sp. and note on freshwater ascomycetes with dimorphic ascospores. Nova Hedwigia 62:513–520

Vijaykrishna D, Hyde KD (2006) Inter- and intra-stream variation of lignicolous freshwater fungi in tropical Australia. Fungal Divers 21:203–224

Zhang Y, Crous PW, Schoch CL, Hyde KD (2012) Pleosporales. Fungal Divers 53:1–221. https://doi.org/10.1007/s13225-011-0117-x

 

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