Helicomyces Link, Mag. Gesell. naturf. Freunde, Berlin 3(1-2): 21 (1809).
Saprobic on woody substrata. Mycelium composed of partly immersed and partly superficial, pale brown, septate, sparsely branched hyphae, with masses of crowded conidia. Sexual state:Ascomatasuperficial, seated on a thin subiculum, uniloculate, subglobose, clavate to obovate, coriaceous, solitary to gregarious, pale brown to reddish-brown, centrally ostiolate, perhaps collapsing when dry, with radiating mycelium or appendages at base. Peridiumcomposed of cells of textura angularis, with external pale yellow, or brownish to brown layer, with inner hyalinelayer. Hamathecium comprising numerous 1–2 µm wide, filiform septate, branched, anastomosing, hyaline pseudoparaphyses. Asci 8-spored, bitunicate, fissitunicate, saccate or cylindric-clavate, apically rounded, with or without an ocular chamber, long pedicellate. Ascospores overlapping fasciculate, elongate, cylindric-subfusiform or narrowly oblong, tapering towards narrow, subacute ends, 10–11-septate, not constricted at septum, hyaline, occasionally pale brown, guttulate when immature, smooth-walled.Asexual state:Conidiophoresmacronematous, erect, short, septate, thick-walled, pale to moderately dark brown. Conidiogenous cells monoblastic or polyblastic, terminal or intercalary, integrated, subhyaline, denticulate. Conidia loosely coiled 2½–4 times, becoming loosely uncoiled in water, conidial filament 4.5–6 µm wide, rounded at apical end, hyaline to pale yellow, multiseptate, with up to 56-septate, slightly constricted at septum, smooth-walled.
Type species: Helicomyces roseus Link
Notes: The genus Helicomyces Link (1809) typified by H. roseus Link is characterized by slender, loosely coiled, multiseptate, hyaline, helicoid conidia that are filamentous and white to pinkish in mass. Helicomyces roseus is frequentlyassociated with an asexual state referred to as Tubeufia cylindrothecia as first determined by Seaver and Waterston (1940) and later by Barr (1980). Tsui and Berbee (2006) and Tsui et al. (2006, 2007) have shown that species referred to as Helicomyces are polyphyletic with sexual states in Acanthostigma and Tubeufia. According to our phylogenetic study (Fig. 2), we therefore treat Clade G as Helicomyces sensu stricto based on authentic sequences of Helicomyces roseus CBS 283.51 with 76% BS and 0.99 PP support. Two isolates of Tubeufia paludosa (CBS 120503 as epitype and AR 4206) and two species of Helicosporium (H. indicum and H. talbotii) cluster with an isolate of H. roseus CBS 283.51 in Helicomyces sensu stricto.