Thallus immersed within the bark of the host (Crataegus twigs), not lichenized.
Anamorph: conidiomata pycnidiate. Pycnidia c. 100 µm in diameter, neatly distributed, in quite densely scattered, extensive colonies. Pycnidial wall thin, brown in water, K+ green. Conidia oblong, colourless, 7.5-8 x 2-3 µm.
Teleomorph: ascomata perithecial. Perithecia rather widely scattered, 180 to 200 µm diameter, with a slightly depressed ostiolar region. Perithecial walls comprise an involucrellum and an exciple, these two structures difficult to distinguish as separate on the flanks but the involucrellum seen to extend away laterally from the exciple at the base. The peridium is brown and K+ green, except at the base of the perithecium where the exciple is thin and colourless. The hamathecium is of rather sparsely branched and anastomosed paraphyses up to 2 µm wide. The asci are cylindrical to very narrowly clavate, c. 45 x 8 µm, with a thickened apex, K/I-. There is a narrow ocular chamber which extends up into the tholus from the ascoplast as a narrow tube which is slightly thickened at its apex. The asci are 8-spored, the ascospores arranged irregularly biseriate. Ascospores colourless, 1-septate, the cells of equal length but the upper cell slightly wider, slightly constricted at the septum, 9-11 x 3.8-4 µm. Each cell of the ascospore contains 1 to 4(5) guttules.