Description
Less than 1cm: Use magnifying glass.
Fruit-body cushion-shaped on a flat base, Ø 1-2 mm, black. Perithecia bottle-shaped, black, rupturing the bark from a stroma in groups of up to ten. Stroma appears in the shape of a dingy white disc or collar. In damp circumstances the cytospora, resembling a red filament, is pushed through a central opening in the stroma.
Occurrence
On branches of poplars. Winter to spring.
Saprophyte.