Teleomorph: Stromata as numerous minute conical pustules, the ectostroma usually obliterated by the perithecial necks, containing 1-8 scattered to clustered ascomata. Ascomata (180–)210–260(–330) μm high × (280–)300–350(–415) μm diam, black, globose, each with one neck. Neck (80–)160–205(–220) μm long, (70–)80–105(–120) μm diam at the base, (64–)78–108(–128) μm diam at apex, central to eccentric, cylindrical, thick, usually thicker toward apex, upright, diagonally straight, or curved, closely appressed when in groups, the apex usually paler. Peridium 18-27 µm thick, composed of 4-5 layers of dark-walled cells. Asci clavate, (54–)60–63(–69) × (14–)15–18(–20) μm, apical ring 3.0–4.0 μm diam, with eight ascospores arranged obliquely parallel to multiseriate. Ascospores (16–)18–20(–22) × 4–5 μm, l/w ratio (3.2–)3.9–4.5(–4.9), ellipsoidal-fusiform, tapering toward rounded ends, curved or straight, tardily septate with one median to submedian septum, constricted, with four refractive bodies of various shapes, often globose, without appendages.
Description contributed by Graham Kinsey (CABI), adapted with data from Mejía et al. (2011). The species is more frequently known as Cryptodiaporthe salicina, and has been confused in the past with P. salicella, which has narrower ascospores.