Collemopsidiales » Xanthopyreniaceae


Xanthopyrenia Bachm., Nova Acta Acad. Caes. Leop. -Carol. German. Nat. Cur. 105(1): 65 (1919).

Index Fungorum number: IF 5810; Facesoffungi number: FoF 07654, 2 morphological species (Species Fungorum 2022), no molecular data available.

Lichen-forming fungi, lichenicolous or forming loose associations with cyanobacteria. Vegetative hyphae usually hyaline. Sexual morph: Ascomata perithecioid, solitary or in groups, superfcial or immersed in the substrarum, subglobose. Peridium thin to thick, composed by elongated to roundish, more or less compresed cells of textura angularis. Involucrelum present in some species, with textura intricata. Hamathecium comprising thin, septate, highly branched and anastomosed interascal filaments. Asci 4–8-spored, thick-walled, bitunicate, fissitunicate, ovate to clavate, apedicellate, with a distinct ocular chamber. Ascospores irregularly arranged within the ascus, ellipsoid to broadly ellipsoid, hyaline, uniseptate, wall cell smooth, usually with a gelatinous shell. Asexual morph: Coelomycetous. Pycnidium, superficial or immersed in the substratum, black, with a small ostiole. Pycnidial wall thick-walled cells of textura angularis, composed of ± isodiametric or elongated cells. Conidiogenous cells cylindrical, phialidic. Conidiospores bacilliform to ellipsoid (adapted from Hongsanan et al. 2020b).

 Type species: Xanthopyrenia tichothecioides (Arnold) Bachm.

Notes: Xanthopyrenia is characterised by perithecioid, solitary ascomata, ovate to clavate, apedicellate asci, and ellipsoid to broadly ellipsoid, hyaline,uniseptate ascospores. The asexual morph is characterised by superficial or immersed pycnidia, cylindrical, phialidic conidiogenous cells and bacilliform to ellipsoid conidia. Zahlbruckner (1926) erected Xanthopyreniaceae to accommodate Xanthopyrenia. Xanthopyrenia tichothecioides was previously known as Arthopyrenia tichothecioides but was not congeneric with the type of Arthopyrenia, A. cerasi. Xanthopyrenia tichothecioides was later combined into Pyrenocollema (P. tichothecioides) based on association with cyanobacteria, perithecioid ascomata, branched and anastomosed interascal filaments and hyalineuniseptate ascospores (Santesson 1992; Coppins et al. 1992; McCarthy and Kantvilas 1999; Nordin 2002). Grube and Ryan (2002) mentioned that P. tichothecioides is not congeneric with the type species of Pyrenocollema as the latter is a parasite on Nostoc and transferred several species to Collemopsidium (Grube and Ryan 2002; Mohr et al. 2004). Molecular data is lacking for Xanthopyrenia. Xanthopyrenia is a distinct and type genus of Xanthopyreniaceae. Fresh collections and DNA sequence data are required to confirm the taxonomic placement of the genus.



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