Saprobic on decaying wood of Edgeworthiachrysantha. Sexual morph: see Hawksworth (1985). Asexual morph: Colonies on the natural substrate superficial, effuse, gregarious, dark brown to black, glistening. Mycelium immersed, composed of branched, septate, thin-walled, smooth, brown hyphae. Conidiophores 253–396 × 8–15.5 µm (x̄= 334.6 × 11.7 µm, n = 20), macronematous, mononematous, erect, straight or flexuous, cylindrical, septate, smooth, brown to dark brown, becoming paler towards the apex and comprising numerous short branches. Conidiogenous cells 14.5–29 × 5–10 µm (x̄= 20.6 × 6.8 µm, n = 30), tretic, integrated, sometimes percurrent, terminal, doliiform or lageniform, subhyaline to pale brown, with new cells developing from the apical or subapical part of the subtending cells. Conidia 32–56.5 × 11–19.5 µm (x̄ = 42.3 × 14.5 µm, n = 30), solitary, acrogenous, cylindrical, sometimes clavate, 3–4-septate, constricted and darker at the septa, smooth, brown and rounded at the apex.

Conidia germinating on Potato Dextrose Agar (PDA) within 24 h, and producing germ tubes either from the apex or base. Colonies circular, flat, dense, radial sulcate, edge entire, pearl-gray on the surface, dark brown on the reverse and becoming grey-white along the margin.

China • Guizhou Province, Zunyi City, Suiyang County, saprobic on decaying branches of Edgeworthiachrysantha, 13 February 2023, Xue-Mei Chen, SY12 (GZAAS 23-0807), living culture GZCC 23-0731.

China (Su et al. 2016; this study).

Edgeworthiachrysantha (This study), Unidentified decaying wood (Su et al. 2016).

Morphologically, our collection matches the characteristics of Kirschsteiniotheliaatra, including macronematous, mononematous conidiophores with numerous short branches; tretic, doliiform, or lageniform conidiogenous cells that develop new cells from the apical or subapical part of the subtending cells; and cylindrical, occasionally clavate conidia that are 3–4-septate, constricted and darker at the septa, which are rounded at the apex (Su et al. 2016). In the phylogenetic analyses, our collection (GZCC 23-0731) clusters with Kirschsteiniotheliaatra (CBS 109.53, DEN, MFLUCC 15-0424, MFLUCC 16-1104 and S–783) (Fig. 1). Excluding gaps, no difference was observed in the comparison of nucleotides across the ITS (491 bp), LSU (788 bp) and SSU (844 bp) regions between our collection and Kirschsteiniotheliaatra (MFLUCC 16-1104). Based on these findings, we identify our isolate as Kirschsteiniotheliaatra, following the guidelines established by Jeewon and Hyde (2016) and Maharachchikumbura et al. (2021). This is the first time Kirschsteiniotheliaatra has been reported from Edgeworthiachrysantha.