Chaetosphaerella phaeostroma  

Stromata absent. Ascomata 200-350 µm diam, ± globose to turbinate, hardly papillate, black, leathery to carbonaceous, usually rather rough-walled, superficial, usually in dense clusters and interspersed with mycelial elements with colonies often several centimetres in diam; the ostiole very inconspicuous and formed late in development, periphysate and surrounded by mid brown thick-walled periphysis-like hyphae. Subiculum composed of a dense mat of dark brown to black thick-walled rather irregular branched hyphae, often setose with acuminate tips and with occasional swellings adjacent to septa, some hyphae fertile. Peridium composed of an outer layer of very thick-walled dark brown cells intermediate between textura angularis and globulosa to ca 9 µm diam, with a distinct and separable inner layer of very thin-walled strongly flattened hyaline textura angularis. Interascal tissue composed of thin-walled filiform paraphyses, usually deliquescent at maturity. Asci 112-128 x 14-18 µm, narrowly cylindric-clavate, short-stalked, thin-walled at all stages, the apex obtuse  to rounded without a clearly defined apical ring, 8-spored. Ascospores arranged biseriately, (22-)31-36 x 6-9 µm, ellipsoidal to cylindric-ellipsoidal, 3-septate with one median septum and two further ones twoards the apices, hardly constricted, the middle cells golden brown and the end ones ± hyaline, smooth, without a mucous sheath.

Anamorph: Oedemium minus fide Hughes & Hennebert (1963), Müller & Booth (1972). Conidiomata absent. Conidiophores 300-400 µm x 7-9 µm, sparsely branched, often with nodose swellings on one or both sides of septa, dark brown towards the base, slightly paler towards the apex. Conidiogenous cells not clearly differentiated from the conidiophores, swollen at the apex to ± 15 µm diam, conidia formed in clusters of up to 6 with sympodial proliferation, without clearly defined denticles, sometimes proliferating to produce further growth and a new ampulliform fertile region, the conidia not catenate. Conidia 20-35 x 10-15 µm, ± cylindrical with rounded ends, mid brown, 3-septate with the end cells paler and somewhat shorter than the middle ones, hardly constricted at the septa, fairly thick-walled, smooth, without gelatinous appendages or sheath, the scar usually inconspicuous.

Vegetative hyphae dark brown, thick-walled, septate, frequently branching.