Below is a list of genera that have been extracted from orchid roots or that are known to germinate orchid seeds. The intention is to build a reference for orchid germination and culture. Since the field of mycology is esoteric to say the least, added data needs to be verifiable by references.
The majority of orchid species appear to associate with Rhizoctonia species which fall into the rather distantly related genera Sebacina, Tulasnella, Thanatephorus and Ceratobasidium. However, some orchids associate with even more distant genera such as Russula and Thelephora. However, with one exception (Epipactis helleborine and Tuber spp.), all well documented orchid associates belong to the Basidiomycota. 1)
There is a great deal of contradictory data on the classification of individual strains and species of these fungi. To draw a line we're adopting the data according to the Index Fungorum
Each genus-page has a listing for a number of genera (underlined). For each genus the experience with one of its strains is explained briefly, different entries are splitted by a paragraph and end with a citation. An entry starts with "Teleomorph identity" when the strain has been determined after the production of fruiting bodies. Entries which don't start with this identity must be assumed anamorphic, refer to the publication cited for more details.