Ocellularia diospyri has a smooth, shiny, oliveaceous
thallus with a thick
cortex. The
apothecia occur solitarily and are immersed in the
medulla. They have a diameter of 0.6–0.65 mm, with a brown, fused exciple. The columella (the sterile central axis of the apothecia) is carbonized (blackened) and is visible from the small apothecial pore; it measures 0.08–0.2 mm in diameter. The
ascospores are thin walled, spindle-shaped, and have from 12 to 23 locules (cavities); they typically measure 102.5–164.5 by 15.0–20.5
μm. This is unusually long for columellate species in the genus
Ocellularia.
O. diospyri contains the
secondary compounds stictic acid and
constictic acid. ==See also==