Ascobolus immersus

A coprophilous fungus exclusive to dung of herbivorous animals, with ascomata 0.5 to 1.5 mm in diameter and up to 1.5 mm in height, appearing on dung gregariously, isolated or in small groups.

Hyphae of the ectal excipulum angular, moderately thick-walled, 10 to 40 µm long and 9 to 25 µm wide.

Asci clavate, 8-spored, often exceeding 300 µm in length, up to 110 µm wide, with spore arrangement within the ascus biseriate to irregular, occupying practically the entire surface of the ascus.

Paraphyses filiform, simple or branched from the base, smooth, hyaline, septate, 2 to 3.5 µm wide, without apical enlargements.

Ascospores broadly ellipsoid, hyaline in youth, gradually turning dark violet with development, 55 to 65 µm long, 30 to 35 µm wide, with a mucous sheath surrounding them—this sheath already visible in many cases inside the ascus and staining with Congo Red—with several irregular striations on their surface depending on the focal plane.