Fungalpedia – Note 3145, Xanthonectria
Xanthonectria J. Fourn. & P.-A. Moreau, in Lechat, Fournier & Moreau, Ascomycete.org 8(4): 173 (2016).
Citation when using this data: Perera RH et al. 2023 – Fungalpedia.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1, Fig 2.
Classification: Xanthonectriaceae, Hypocreales, Hypocreomycetidae, Sordariomycetes, Pezizomycotina, Ascomycota, Fungi.
Saprobic on dead plant parts in terrestrial habitats, sometimes on wood submerged in freshwater. Sexual morph: Ascomata perithecial, 240–380 μm diam., superficial, astromatic, solitary or in groups of 2–6, sometimes fused, globose, collapsing upon drying, pale yellow to bright yellow or bright orange, KOH-, LA-, surface glabrous, ostiolate. Ostioles minutely papillate, with a periphysate ostiolar canal. Peridium cells forming textura epidermoidea in surface view; vertical section up to 80 μm thick, of three strata, outer stratum formed of subglobose to globose, thick-walled cells; middle stratum of globose to ellipsoidal, thick-walled cells containing scattered orange oily droplets; inner stratum formed of elongated, hyaline, thin-walled cells with abundant orange oily droplets. Paraphyses filamentous, containing orange, oily droplets. Asci 8-spored, unitunicate, fusiform to clavate, short-stipitate, apex rounded, without an apical ring. Ascospores multiseriate, long fusiform, ends rounded, 3–9 septate, hyaline, spinulose. Asexual morph: Hyphomycetous, acremonium-like. Primary conidiophores arising from hyphae, macronematous, mononematous, unbranched, flexuous, hyaline, smooth-walled. Conidiogenous cells monophialidic, with unflared collarette. Conidia aseptate, narrowly ellipsoidal to subcylindrical, apex rounded, base with an abscission scar, hyaline, smooth-walled, held in small slimy drop at tip of phialide. Sporodochia present. Sporodochia 150– 180 μm diam., formed at margin of colony. Conidiophores fasciculate, arising from hyphae. Conidiogenous cells 8–30 μm long, without collarette. Conidia aseptate, narrowly ellipsoidal to subcylindrical, apex rounded, base with an abscission scar, hyaline, smooth-walled, held in large slimy drops (adapted from Lechat et al. 2016a).
Notes: Desmazières (1840) described the hypocrealean fungus Sphaeria pseudopeziza. However, the actual placemet of Sphaeria pseudopeziza was unclear for decades and, was maintained in different genera such as Calonectria, Dialonectria and Nectria by various authors (Desmazières 1840; Saccardo 1878; Rossman et al. 1999). Lechat et al. (2016a) held a different perspective on Sphaeria pseudopeziza (as Nectria pseudopeziza) and recognized its resemblance to Bionectriaceae. They introduced the monotypic genus Xanthonectria to accommodate Nectria pseudopeziza and placed it in Bionectriaceae based on morphology, culture characteristics and, LSU and ITS phylogeny. Xanthonectria is characterized by astromatic, superficial, soft-textured, glabrous, bright coloured ascomata without KOH or lactic acid reactions, multi-septate, long fusiform, ascospores and acremonium-like asexual morph. In current study Xanthonectria groups sister to the clade representing Bullanockia with high statistical support (94% MLBT; 100% BYPP, Perera RH et al. 2023).
Known distribution: Worldwide (Lechat et al. 2016a, This study)
Type species: Xanthonectria pseudopeziza (Desm.) Lechat, J. Fourn. & P.-A. Moreau, in Lechat, Fournier & Moreau, Ascomycete.org 8(4): 173 (2016).
Other accepted species: Species Fungorum – search Xanthonectria.
Figure 1 – Xanthonectria pseudopeziza (MFLU 16-0513) a Herbarium material b–d Ascomata on host (d rehydrated with water) e Vertical section of ascoma f Vertical section of peridium g–k Asci l–r Ascospores. Scale bars: d = 500 µm, e = 200 µm, f = 20 µm, g–k = 50 µm, l–r = 20 µm.
Figure 2 – Xanthonectria pseudopeziza (CLL15075, redrawn from Lechat et al. 2016a) a Sporodochia at margin of the colony b Primary conidiophores and conidia c Conidiophores from sporodochium d Conidia. Scale bars: a = 100 µm, b, c = 10 µm, d = 5 µm.
References
Rossman AY, Samuels GJ, Rogerson CT et al. 1999 — Genera of Bionectriaceae, Hypocreaceae and Nectriaceae (Hypocreales, Ascomycetes). Stud Mycol 42:1–248.
Saccardo PA (1878) Enumeratio Pyrenomycetum Hypocreaceorum hucusque cognitorum systemate carpologico dispositorum. Michelia 1:277–325.
Entry by
Perera RH, Guizhou Key Laboratory of Agricultural Biotechnology, Guizhou Academy of Agricultural Sciences, Guiyang, Guizhou 550006, P. R. 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, Mushroom Research Foundation, 128 M.3 Ban Pa Deng T. Pa Pae, A. Mae Taeng, Chiang Mai 50150, Thailand.
Published online 17 September 2026.