The name
Ceratobasidium was introduced in 1935 by American mycologist D.P. Rogers to accommodate species of the old
form genus Corticium that showed affinities with the
heterobasidiomycetes. These affinities were the possession of large
sterigmata ("cerato basidium" means "horned
basidium") and the production of
basidiospores that produce secondary spores. Four species were originally placed in the genus, with subsequent authors adding a further 35 species. The genus
Ceratorhiza was introduced for
anamorphs of
Ceratobasidium by
R.T. Moore in 1987, distinguishing them from anamorphs of
Thanatephorus which were retained in
Rhizoctonia.
Current status Molecular phylogenetic analysis of
DNA sequences, places
Ceratobasidium (excluding the type species) within the Cantharellales. Research on the
septal pore ultrastructure of the little-known and atypical type species,
Ceratobasidium calosporum, indicates that it is a member of the
Auriculariales and is unrelated to other species of
Ceratobasidium. On this basis, Oberwinkler et al. (2013) concluded that the name
Ceratobasidium should only be applied to the type–
C. calosporum—and that this taxon was more appropriately placed in the Sebacinaceae based on shared characters between
C. calosporum and
Sebacina calospora (syn.
Ceratosebacina calospora). Following changes to the
International Code of Nomenclature for algae, fungi, and plants, the practice of giving different names to teleomorph and anamorph forms of the same fungus was discontinued, meaning that
Ceratorhiza became a synonym of the earlier name
Ceratobasidium. DNA evidence also placed
Ceratobasidium species (excluding the type species) in the genus
Rhizoctonia. As of 2025,
Ceratobasidium and several other genera were formally synonymised under a unified
Rhizoctonia. The genus
Rhizoctonia now encompasses names formerly circumscribed under
Moniliopsis,
Ceratobasidium,
Thanatephorus,
Uthatobasidium,
Koleroga,
Cejpomyces,
Oncobasidium,
Ypsilonidium,
Ceratorhiza, and
Tofispora.
Species now placed within Rhizoctonia Following the generic revision completed by O'Donnell et al. (2025) , the following names are now placed within
Rhizoctonia: •
Ceratobasidium albasitensis =
Rhizoctonia klebahnii •
Ceratobasidium anceps =
Rhizoctonia anceps •
Ceratobasidium angustisporum =
Rhizoctonia angustispora •
Ceratobasidium australiense (as
australiensis) =
Rhizoctonia australiensis •
Ceratobasidium bicorne =
Rhizoctonia bicornis •
Ceratobasidium bulbillifaciens =
Rhizoctonia bulbillifaciens •
Ceratobasidium chavesianum (as
chavesanum) =
Rhizoctonia chavesiana •
Ceratobasidium cornigerum =
Rhizoctonia cornigera •
Ceratobasidium erinnae =
Rhizoctonia erinnae •
Ceratobasidium globisporum =
Rhizoctonia globispora •
Ceratobasidium gomesae =
Rhizoctonia gomesae •
Ceratobasidium korinnae =
Rhizoctonia korinnae •
Ceratobasidium lantanae-camarae =
Rhizoctonia lantanae-camarae •
Ceratobasidium myrtisiae =
Rhizoctonia myrtisiae •
Ceratobasidium niltonsouzanum =
Rhizoctonia niltonsouzana •
Ceratobasidium noxium =
Rhizoctonia noxia •
Ceratobasidium obscurum =
Rhizoctonia obscura •
Ceratobasidium papillatum =
Rhizoctonia papillata •
Ceratobasidium praticola nom. inval. =
Rhizoctonia praticola •
Ceratobasidium praxillae =
Rhizoctonia praxillae •
Ceratobasidium pseudocornigerum =
Rhizoctonia pseudocornigera •
Ceratobasidium queenslandicum =
Rhizoctonia queenslandica •
Ceratobasidium ramicola =
Rhizoctonia ramicola •
Ceratobasidium sapphoae =
Rhizoctonia sapphoae •
Ceratobasidium setariae =
Rhizoctonia setariae •
Ceratobasidium solani =
Rhizoctonia solani •
Ceratobasidium sphaerosporum =
Rhizoctonia sphaerospora •
Ceratobasidium sterigmaticum =
Rhizoctonia sterigmatica •
Ceratobasidium stridii =
Rhizoctonia stridii •
Ceratobasidium terrigenum =
Rhizoctonia terrigena •
Ceratobasidium theobromae =
Rhizoctonia theobromae •
Ceratobasidium tradescantiae =
Rhizoctonia tradescantiae Redisposition of former species Names previously placed within
Ceratobasidium that are now placed in other genera are listed below. Refer to O'Donnell et al. (2025) for a summary of 66 invalid/illegitimate names and 34 names of uncertain application (nomina dubia), some of which are names under
Ceratobasidium. •
Ceratobasidium atratum =
Scotomyces subviolaceus (
Hydnaceae) •
Ceratobasidium fibrillosum =
Oliveonia fibrillosa (
Oliveoniaceae) •
Ceratobasidium mycophagum =
Syzygospora mycophaga (
Filobasidiaceae) •
Ceratobasidium pearsonii =
Paullicorticium pearsonii (
Hydnaceae) •
Ceratobasidium plumbeum =
Scotomyces subviolaceus (
Hydnaceae) •
Ceratobasidium striisporum =
Xenasma pulverulentum (
Xenasmataceae) •
Ceratobasidium subatratum =
Scotomyces subviolaceus (
Hydnaceae) •
Ceratobasidium vagum =
Botryobasidium vagum (
Botryobasidiaceae) ==Description==