Rhizoctonia angustispora (Warcup & P.H.B. Talbot) R.P. O’Donnell, C.C. Linde & T.W. May, comb. nov. MB 852035. Basionym: Ceratobasidium angustisporum Warcup & P.H.B. Talbot, New Phytol. 86 (3): 267. 1980. Type citation: ‘ Holotypus: Herb. ADW No. 16594, J. H. Warcup (0507) (described 1971 as C. sp.) … Host: Pterostylis mutica R. Br., Hincks, Eyre Peninsula, South Australia.’ According to Roberts (1999) the type ‘cannot now be found’. ITS barcode: AJ427403 (T). UNITE 1.5 % SH: SH0987490.10FU. Alternative markers: ATP6 = DQ301591 (T); LSU = MH873364 (T); RPB2 = DQ301722 (T). Ex-type culture: CBS 568.83. Notes: Roberts (1999) treated this taxon as conspecific with R. pseudocornigera, despite the highly disjunct distribution between the type of Ceratobasidium angustisporum (Australia) and the type of R. pseudocornigera (Denmark). The type specimen of R. pseudocornigera has to date not been sequenced; however, the ex-type culture of Cb. angustisporum has been sequenced. Sequences of Cb. angustisporum are curated in the UNITE database as species hypothesis SH0987490.10. Sequences corresponding with this species hypothesis from global soil samples appear to have only been identified in Australia and South Africa, supporting the proposition that this taxon is distinct from the northern hemisphere R. pseudocornigera.

Published as part of O'Donnell, R. P., Linde, C. C. & May, T. W., 2025, Rise up, Rhizoctonia: moving to one fungus, one name in the Ceratobasidiaceae (Agaricomycetes, Cantharellales), pp. 285-325 in Persoonia 54 (1) on page 301, DOI: 10.3114/persoonia.2025.54.09, http://zenodo.org/record/17127619