Eleutheromyces Fuckel, Jb. nassau. Ver. Naturk. 23-24: 183 (1870) [1869-70]
Leotiomycetes, Leotiomycetidae, Phacidiales, Helicogoniaceae
Fungicolous on agarics. Sexual morph: undetermined. Asexual morph: Conidiomata yellowish brown, salmon or black, pycnidial, solitary to gregarious, deeply immersed or immersed to semi-immersed, oval or globose to subglobose, unilocular, glabrous, gelatinous, thick- and smooth-walled, papillate, ostiolate. Ostiole circular, single, centrally located. Conidiomatal wall composed of textura angularis with thick-walled cells, dark brown to paler towards the conidial hymenium. Conidiophores arising all around the cavity of the conidiomata, hyaline, often branched and broader at base, septate, smooth-walled, invested in mucus. Conidiogenous cells hyaline, enteroblastic, phialidic, subcylindrical to lageniform, integrated with the conidiogenous loci immediately below the septa, smooth-walled. Conidia hyaline, ellipsoidal or lenticular or cylindrical, unicellular, bearing tubular, attenuated appendages at each end, appendages delimited from the conidium body by septa; basal appendage developing before the conidium body.
Type species: Eleutheromyces subulatus (Tode) Fuckel, Jb. nassau. Ver. Naturk. 23-24: 183 (1870) [1869-70]
Notes: Fuckel (1870) proposed Eleutheromyces based on E. subulatus, a fungus reported from North America and Europe on decayed fleshy fungi (Sutton 1980, Sigler 1990, Tsuneda et al. 1997). Seeler (1943) described conidiogenesis in E. subulatus as phialidic. He also redescribed the genus Eleutheromycella (type species E. mycophila Höhn.) and differentiated it from Eleutheromyces by its darker, shorter pycnidia and longer, more slender conidia. This generic concept was endorsed by Sutton (1980). However, Nag Raj (1993) did not agree and regarded these two as congeneric, since both share similar form of conidiomata, conidiogenous cells and conidia. The difference noted by Seeler (1943) is therefore used only at the species level. Sigler (1990) reported a Hyphozyma synasexual morph for E. subulatus. Subsequently, Tsuneda et al. (1997) found that this morph causes black spot disease on Lentinula edodes (Berk.) Pegler. Crous et al. (2014a) epitypified E. subulatus with the strain CBS 113.86 (incertae sedis, Helotiales), and two cultures listed in CBS collection as E. subulatus (CBS 113.86 and CBS 458.88) were found to be phylogenetically and morphologically distinct. Crous et al. (2015d) added an additional species, E. pseudosubulatus Crous & A. Giraldo found on Lactarius scrobiculatus (Scop.) Fr., based on its narrower conidia with longer appendages. We re-examined the type species of E. mycophila and found that it shares similar morphology of conidiomata, conidiogenous cells and conidia with E. pseudosubulatus, except the condiomata are dark brown to black in E. mycophila and salmon in E. pseudosubulatus. Moreover, conidia of E. pseudosubulatus (5–6 × 1.5–2 µm) fall into the range of E. mycophila (4–13 × 1–3.5 µm). Therefore, E. pseudosubulatus is reduced to synonymy under E. mycophila, and the colour differences noted here may reflect intraspecific variation. Additional collections need to be studied to verify this hypothesis. Thus, two species are accepted in the genus, viz. E. mycophila and E. subulatus.
Distribution: Austria, Canada, Germany, France, Latvia, Sweden, UK (Nag Raj 1993, Crous et al. 2014a, 2015d, this study).
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.