Rhizoctonia gardneri (Warcup) O’Donnell, R. P., Linde, C. C. & May, T. W., 2025

Rhizoctonia gardneri (Warcup) R.P. O’Donnell, C.C. Linde & T.W. May, comb. nov. MB 852057 View Materials .

Basionym: Thanatephorus gardneri Warcup, Mycol. Res. View in CoL 95 (6): 658. 1991.

Type citation: ‘ Holotypus: Herb ADW 17023 About ADW , J. H . Warcup, ex Rhizanthella gardneri, Corrigin , W. A., 11 February 1986.’ [ MEL 2146230 View Materials ]

ITS barcode: GQ175295 View Materials ( R).

UNITE 1.5 % SH: SH0897913.10FU.

Alternative marker: LSU = GQ200563 View Materials (R).

Notes: Considered a nomen dubium by Roberts (1999) on the basis that the herbarium specimen had been lost. However, the herbarium specimen has since been located at the National Herbarium of Victoria (MEL) and digitised (MEL 2146230). The specimen is a dried agar culture and sequencing of this specimen was attempted by us but failed. Bougoure et al. (2009) isolated and sequenced a species of Ceratobasidiaceae from the orchid Rhizanthella gardneri from the type locality of Thanatephorus gardneri (Sorensons Reserve, Corrigin, W.A.), which was later designated as ‘OTU C’ sensu Freestone et al. (2021). Based on the specificity of the mycorrhizal associations of R. gardneri ( Warcup 1985, 1991, Bougoure et al. 2009, 2010), the taxon identified by Bougoure et al. (2009) is almost certainly conspecific with Th. gardneri . A sequence from Bougoure et al. (2009) isolated from R. gardneri from the type locality (which was recovered within the Rhizoctonia clade in our analysis) is taken as a representative sequence here.