Anamorph: Leptostroma-like. Conidiomata subcutiular, (180-) 300-600 x 150-250 µm, frequently aggregating into much larger compound structures, irregular in form but mostly elliptical to oblong in outline, strongly flattened, often confluent, dark brown to black. Upper wall composed of small dark brown thick-walled angular cells, almost completely occluded by melanized material, opening with irregular longitudinal splits and possibly also with ostioles. Lower wall composed of several layers of small mid brown angular cells 5-7 µm diam. Conidiophores absent. Conidiogenous cells mostly developing from a hyaline subconidiogenous layer above the lower wall, . Conidiogenous cells 3.5-5 x 2-2.5 µm, conical to ovoid or doliiform, proliferation unclear. Conidia 4-5.5 x 1-1.5 µm, fusiform-cylindrical to allantoid, usually slightly curved with one face ± flat, aseptate, hyaline, thin-walled, smooth, without an epispore, gelatinous sheath or appendages. Teleomorph: ascostromata thyriothecia, ca 0.3 mm long but often confluent into larger crusts 2-3 mm in length and 1-1.5 mm broad, elongate along the petioles, ± elliptical in outline, subcuticular. Lower wall well-developed, composed of several layers of small angular cells 5-7 µm diam., at first hyaline and becoming mid brown. Interascal tissue composed of numerous short cellular pseudoparaphyses. Asci ca 30 x 12 µm, broadly cylindrical, 8-spored but often with some aborting. Ascospores 12-15 x 3-4 µm, ± allantoid, the ends obtuse to acute, usually 1-septate but with a proportion of spores developing one or two further septa, hyaline, thin-walled.
Teleomorph description adapted from Holm & Holm (1977). The connection between anamorph and teleomorph is uncertain; Holm & Holm indicate that the species has an anamorph belonging to Leptostroma but do not provide any further details. It does not appear to be the same as the species treated as L. filicinum by Grove (1937).