Xylaria cinerea  

Anamorph: Conidiomata absent. Conidiophores in palisades on the surface of the upper part of stromata, 7–16 × 3–4 μm, cylindrical, frequently branched near the base, proliferating sympodially and bearing denticular conidial secession scars. Conidia 4–5.5 × 2–4 μm, ellipsoidal, aseptate, hyaline, thin- and smooth-walled, without a gelatinous sheath or epispore.
Teleomorph: stromata (8-) 12-20 (-35) x 2-4 mm, upright, solitary or in clusters of two or three, usually ± sessile but with a narrow stipe to ca 30 mm in length when growing on the undersurface of rotten logs, fusiform to cylindrical with rounded to apiculate sterile apices, sometimes nodulose with irregular circular or longitudinal wrinkles. Surface ± smooth in young stromata, consisting of a pale grey to cream-coloured fibrous outer layer which splits longitudinally into broad strips and is progressively worn off. Mature stromata black, sometimes with greyish patches. Outer stromatal layer 40–50 μm thick, leathery, the interior solid, spongy, white to cream-coloured with a slightly darker core at maturity. Ascomata perithecia, usually hardly visible from the surface, 500–600 μm diam., ± globose, sometimes laterally flattened due to pressure from surrounding perithecia. Ostioles faintly to distinctly papillate, bluntly conical, black, 120–170 μm diam, opening between the white plates. Interascal tissue composed of copious thin-walled rarely branched paraphyses 2-3 µm diam. Asci 160–195 μm in total length, the spore-bearing parts 95–125 × 9–10.5 μm, cylindrical, fairly thick-walled but not fissitunicate, the apex obtuse to rounded, with a complex tubular apical ring 3.5–4 μm high × 2.5–3 μm diam. bluing in in iodine, 8-spored. Ascospores ± uniseriately arranged, 13–16 × 5–6 μm,  ellipsoidal- to fusiform-inaequilateral with acute to obtuse ends, one end often slightly more pointed and sometimes slightly beaked, dark brown, smooth, biguttulate, with a straight to slightly sinuous germ slit extending most of the length of the spore on the less convex side. some populations with a persistent but inconspicuous hyaline cellular appendage at one or both ends.