Melanconis stilbostoma  

Conidial morph acervular, mixed with stromata of the ascal morph or developing separately, conspicuous, initially with a central column of white fungal tissue forming within the bark, becoming surrounded by a sterile yellow margin and narrow discs rupturing the epidermis, followed by the production of conidia in olivaceous to black chambers containing black conidial masses. Conidiomata 0.9–3.2 mm diam., subconical or pulvinate, scattered or crowded. Conidiophores emerging around the central column from a pseudoparenchymatous base, filiform, branched near the base and usually asymmetrically at higher levels, first hyaline, turning brown from their tips; terminal conidiogenous cells (11.5–) 18–33 (–42.5) × (2– ) 2.5–3.5 (–4.5) μm, ± cylindrical, with up to 5 or 6 annellations. Conidia (10.5–) 12.5–15 (–17.5) × (6.2–) 7.2–8.5 (–9.5) μm, ovoid, ellipsoidal or subglobose, aseptate, dark brown, thick-walled, smooth, with a small scar.
Ascal morph formed within pseudostromata to 3.5 (–4.5) mm in diam., scattered to aggregated, usually distinctly projecting from the bark surface, pulvinate with a bluntly conical centre (projecting disc), consisting of an ectostromatic disc and perithecia embedded in an entostroma around a central column and often chambers filled with conidia. Ectostromatic discs 0.4–2.4 (–2.7) mm diam., white or pale yellow, brownish when old, often completely obscured by the ostiolar necks. Ostiolar necks cylindrical, laterally or centrally attached, convergent, shiny black. Entostroma consisting of hyaline hyphae and bark cells. Perithecia (450–) 540–700 (–780) μm diam., arranged in a valsoid configuration around and below the central column, globose to subglobose, collapsing upon drying. Peridium consisting of a dark brown small-celled outer and a hyaline to brownish, large-celled inner layer. Interascal tissue absent at maturity. Asci (69–) 80–123 (–141) × (10–) 13–18 (–21) μm, cylindric-clavate, deliquescent at the base and floating free at maturity, the apex rounded with a refractive apical ring that stains in ink, (4-) 8-spored.  Ascospores obliquely uniseriate, (13.7–) 16–19 (–23) × (4.7–) 6.5–8.5 (–9.7) μm, at first narrow, fusiform-cylindrical and with small roundish appendages, later becoming broadly ellipsoidal with rounded ends, slightly constricted at the ± median septum, hyaline, thick-walled, smooth, the appendages deliquescing.

Description adapted from Jaklitsch & Voglmayr (2020).