Many isolations from roots of Caladenia and allied genera (Glossodia, Elythranthera and Eriochilus) from southern Australia show that these orchids are closely associated with the endophytic fungus Sebacina vermifera, and that species of Diuris are associated with Tulasnella calospora (Rhisoctonia repens). Back-inoculation experiments with sterilized orchid seed on a medium with cellulose as the carbon source showed that Tulasnella calospora greatly stimulated germination of species of Diuris, whereas Sebacina vermifera and other species of Tulasnella from orchids had little effect. Results with Sebacina vermifera and seed of species of Caladenia have generally been less successful, but in one test the fungus greatly stimulated germination of seed of C. cornea.

Mycelium of Tulasnella calospora was commonly found on and in tubers, growing or dormant, of the species of Diuris examined.