Plagiostoma aesculi
Stromata poorly developed, on fresh dead twigs. Ascomata in groups of 3–10, black, oblate spheroidal when moist, convex, usually with irregular dents on top when dry, 300–450 μm high × 380–600 μm diam. Necks converged with others in group, eccentric to marginal, slightly curved, 420–700 μm long, 100–150 μm wide at base, 60–150 μm wide at apex. Asci fusiform, (45.5–)48.5–67(–78.5) × (10–)12.5–16(–21.5) μm, apical ring absent, with eight ascospores arranged obliquely biseriate to irregularly multiseriate. Ascospores variable in size and shape, ellipsoidal to fusiform, (13–)17.5–20(–23.5) × (3.5–)4–5(–6.5) μm, l:w (2.6–)3.5–4.4(–5.7), two-celled, constricted or not constricted at the median septum, ends rounded to tapering, distal cell often slightly wider than basal; appendages usually absent, if present, subulate, length to 5 μm.
Description adapted from Sogonov et al. (2008). The species has until recently been placed in Cryptodiaporthe; that is now considered a synonym of Plagiostoma by Sogonov et al. (2008) and Mejia et al. (2008). Sutton (1980) describes an anamorph for this species, referred by him to Diplodina aesculi; this is similar to the anamorph of P. salicellum with conidiomata to 1.5 mm diam, conidiophores to 35 x 4 µm and conidia 17-19.5 x 3-3.5 µm, long-fusiform and 1-septate. The correlation between anamorph and teleomorph needs confirmation.
In bark of recently dead twigs of Aesculus hippocastanum.
GB&I: England: Norfolk and Tyne & Wear.