Additional materials examined: USA, California, Palo Alto campus of Stanford University, on dead cankered branches of Eucalyptus globulus, 2001, G.C. Adams (MSC 380711, culture CBS 117005); ibid., Berkeley campus of University of California, on dead twigs of E. globulus, 8 Jun. 2001, G.C. Adams & H. Hallen (MSC 380709, culture CBS 116824). New Zealand, on stem and branches canker of Castanea sativa, unknown date, M. Braithwaite (culture CBS 101714).

Notes: Cytospora berkeleyi was described from dead cankered branches of Eucalyptus globulus in the USA (Adams et al. 2005), and clusters in a sister clade with C. diatrypelloidea. However, C. berkeleyi (CBS 117005) differs from C. diatrypelloidea (CBS 120062) in ITS (0/502), act (0/243), rpb2 (18/650), tef1-α (16/509) and tub2 (5/415) loci. Conidiomata of C. berkeleyi can have both a cytosporoid rosette and torsellioid features (Adams et al. 2005). Currently, this species has been found in the USA and New Zealand on Eucalyptus spp. and Castanea sativa.

Typus: USA, California, Palo Alto campus of Stanford University, on dead cankered branches of Eucalyptus globulus, 2001, G.C. Adams (holotype MSC 380710, ex-holotype culture CBS 116823).

The genus Cytospora includes fungal species that occur mostly on woody plants including angiosperms and gymnosperms. Species of Cytospora (sexual morphs including Leucostoma, Valsa, Valsella and Valseutypella) have a cosmopolitan distribution and are most likely endophytes or latent pathogens in healthy plant tissues. They can also become important pathogens when their host trees are under stress (Schoeneweiss 1981, 1983). In this pathogenic phase, most Cytospora species cause canker diseases (Sinclair et al. 1987, Farr et al. 1989, Fan t al. 2020). The sporocarps of these fungi are then found on the dying wood associated with these cankers.

Conidiomata Group AII (type a7), semi-immersed in bark, erumpent when mature, discoid to conical, 450–750 μm diam, with multi-locule. Conceptacle prominent. Ectostromatic disc white, circular, 85–160 μm diam, with single ostiole per disc in the centre. Ostiole circular to ovoid, black, 35–55 μm diam. Locules multiple, subdivided with common walls. Conidiophores hyaline, unbranched or occasionally branched, 10.5–18.5 × 1–2 μm (av. = 13.8 ± 1.3 × 1.6 ± 0.1 μm, n = 30). Conidiogenous cells enteroblastic, phialidic, subcylindrical to cylindrical, 7.5–11.5 × 1–2 μm (av. = 10.2 ± 1.1 × 1.5 ± 0.1 μm, n = 30). Conidia hyaline, unicellular, eguttulate, elongate-allantoid, 6–8 × 1.5–2 μm (av. = 7.3 ± 0.3 × 1.7 ± 0.1 μm, n = 50). Culture characteristics: Colonies on PDA white, reaching 9-cmdiameter after 6 d at 25 °C, flat, felt-like, with aerial mycelium.

Typus: Germany, on bark, Hoffmann (lectotype designated here plate VI, fig. 3 in Hoffmann (1787), MBT 10017544). Switzerland, on Populus nigra, unknown date, G. Défago (epitype designated here CBS H-19169, MBT 10017505, ex-epitype culture CBS 258.34).

Cytospora pruinosa is distributed worldwide on Fraxinus, Syringa and Olea (Adams et al. 2006, Fan et al. 2020). In the ITS, act1, rpb2, tef1-α and tub2 gene trees, the BI and ML phylogenies all placed it in a distinct clade, with high support (ML/ BI = 99/1, 100/1, 100/1, 100/1 and 100/1, respectively). No type material could be located for this species, but a lectotype can be chosen from Fries, namely Scleromycetes Sueciae 82, which is mentioned in the sanctioning publication (Fries 1823). In the present study, CBS 200.42 is treated as a reference isolate by the same host species and collected continent as type. Valsa cypri which commonly considered a synonym of Cytospora pruinosa is described from Ligustrum vulgare (Défago 1942, Hayova & Minter 1998b), but this needs to be confirmed with sequence data for isolates from the type host.

Ascomata solitary to grouped, immersed in bark. Stromatic tissues delimited by a black marginal line (conceptacle) or not. Ectostromatic disc usually surrounded by tightly ostiolar necks. Perithecial ascostroma inclined to upright, flask-shaped to spherical, arranged circularly or irregularly. Paraphyses present or deliquescent. Asci free floating, ellipsoid to clavate, apical ring chitinoid, refractive. Ascospores hyaline, elongate-allantoid, aseptate, thin-walled, biseriate to irregularly multiseriate, 4, 8 or more per ascus. Conidiomata stromatic or pycnidial, immersed in bark. Stromatic tissues delimited by a black marginal line (conceptacle) or not. Ectostromatic disc prominent or lacking, one to more ostioles per disc. Locules single, undivided to multiple chambered with invaginations. Conidiophores borne along the locules, branched or unbranched. Conidiogenous cells enteroblastic, phialidic. Conidia hyaline, allantoid, aseptate, small and narrow.