Biscogniauxia Kuntze, Revis. gen. pl. (Leipzig) 2: 398 (1891)
Xylariomycetidae, Xylariales, Graphostromataceae, Biscogniauxia
Index Fungorum number: IF 582; 53 morphological species (Species Fungorum 2020), 23 species with sequence data.
Saprobic or parasitic on woody substrates. Sexual morph: superficial, effuse-pulvinate, applanate, solitary or clustered, surface dark brown to black, innermost layer white, with or without margins, bipartite with outer layer dehiscent, KOH-extractable pigments absent, plane or with inconspicuous ascomatal mounds, forming carbonaceous tissue immediately beneath host surface. Ascomata immersed, black, obovoid, monostichous, tubular to long tubular, each individual ascoma surrounded by carbonaceous stromal tissue, tissue between ascomata sometimes woody, inconspicuous to conspicuous, composed of fungal tissue, host tissue, or both. Ostioles at the same level as stromal surface or umbilicate, at times papillate, with punctate openings. Paraphyses hyaline, filamentous. Asci unitunicate, 8-spored, cylindrical, short-pedicellate, apex rounded, apical ring wedge-shaped or discoid, usually J+ in Melzer’s reagent. Ascospores uniseriate to overlapping uniseriate, ellipsoid to short fusoid, uni-bicellular, pale brown or dark brown to black on maturity, rarely both cells remaining hyaline, inequilateral, ends narrowly to broadly rounded, mature ascospores often comprising a hyaline cellular appendage, guttules absent or present, germ slit spanning along entire or less than spore length, straight or sigmoid. Asexual morph: nodulisporium-like or periconiella-like, sometimes forms variations of the latter two types (adapted from Daranagama et al. 2018, Samarakoon et al. 2022).
Type species: Biscogniauxia nummularia (Bull.) Kuntze, Revis. gen. pl. (Leipzig) 2: 398 (1891)
Notes: Biscogniauxia (type species B. nummularia) species are characterised by bipartite stromata lacking KOH-extractable pigments, and short-pedicellate cylindrical asci and ellipsoid to short fusoid ascospores in their sexual and nodulisporium-like or periconiella-like asexual morphs (Daranagama et al. 2018). Biscogniauxia appears paraphyletic with Camillea, Obolarina and Graphostoma (Wendt et al. 2018, Daranagama et al. 2018) (copied from Samarakoon et al. 2022).
Species illustrated in this entry:
Biscogniauxia magna Samarak. & K.D. Hyde
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