Helminthosphaeria corticiorum

A single globose ascoma, barely half a millimeter in diameter, immersed in a wood substrate in an advanced stage of decay beneath a myxomycete.

Peridial hyphae irregular, angular, thick-walled, with strong brown intracellular pigment inside.

Asci cylindric-clavate, mostly uniseriate, some slightly biseriate with irregular spore arrangement in the upper ascus, with an amyloid apical apparatus in Melzer's reagent.

Ascospores ellipsoidal, hyaline, smooth and moderately thick-walled, inequilateral, flattened on one side, with abundant vacuolar internal content.