Acrospermaceae Fuckel, Jb. nassau. Ver. Naturk. 23–24: 92 (1870)

[1869–70], MycoBank: MB 80430
Saprobic, epiphytic or symbiotic on herbaceous plants. Sexual state: Ascomata solitary or in groups, superficial or immersed in stromata, often long, yellowish white to brown, black when dry, club-shaped to conoid, with a short stipe, flattened when dry, swelling when moist, ostiole large. Peridium in horizontal section comprising three layers, an outer layer composed of dark brown cells of textura angularis, a central layer, composed of pale brown tissue of elongated cells, and an inner layer composed of dense tissue of small, light brown cells. Hamathecium of narrow long, pseudoparaphyses or pseudoparaphyses lacking. Asci 8-spored, bitunicate, narrowly cylindrical, pedicellate, apically rounded with an ocular chamber. Ascospores fasciculate, filiform, hyaline, multiseptate, almost as long as the asci, smooth-walled. Asexual state: hyphomycetous. Conidiophores micronematous, pale brown, septate, branched or unbranched. Conidiogenous cells holoblastic, sympodial with denticles, pale brown, smoothwalled. Conidia cylindrical, long ellipsoid, pale yellow, 1–3- septate, smooth-walled.

Notes : The family Acrospermaceae presently includes two genera Acrospermum and Oomyces (Lumbsch and Huhndorf 2010). Acrospermum has club-shaped, brown, uni-locular ascomata and narrow, long paraphyses which resemble ascospores. However, Oomyces has conoid, yellowish white, multi-locular stromata and lacks pseudoparaphyses (Eriksson 1981). The asexual states of this family include members of Dactylaria and Gonatophragmium which are linked to asexual Acrospermum (Wijayawardene et al. 2012). However, Dactylaria was shown to be polyphyletic by Bussaban et al. (2005) and Seifert et al. (2011) also stated that Dactylaria is heterogenous, hence the phylogeny needs clarification. Kirk et al. (2008) mentioned Gonatophragmium is an asexual state of Acrospermum, but Seifert et al. (2011) did not assign any taxonomic affiliation. Whether  Gonatophragmium is polyphyletic is not clear. No asexual state has been reported for Oomyces . Minter et al. (2007) established the order Acrospermales to accommodate this family, and Stenroos et al. (2010) confirmed this unique order belonging to Dothideomycetes by using five-gene.

    Other genera included

    Gonatophragmium Deighton, in Cejp & Deighton, Mycol. Pap. 117: 13 (1969)
    Type species : Gonatophragmium mori (Sawada) Deighton, in Cejp & Deighton, Mycol. Pap. 117: 13 (1969)
    Oomyces Berk. & Broome, Ann. Mag. nat. Hist., Ser. 2 7: 185 (1851)
    Type species : Oomyces carneoalbus (Lib.) Berk. & Broome, Ann. Mag. Nat. Hist., Ser. 2 7: 185 (1851)

    Key to sexual genera of Acrospermaceae
    1. Fruiting bodies ascomata club-shaped, brown, paraphyses long …………………………Acrospermum
    1. Fruiting bodies stomata conoid, yellowish white, paraphyses lacking ………………….Oomyces