Clitocybe Illudens: Its Cultivation, Chemistry, And Classification

Abstract

SUMMARY Clitocybe illudens is a tetrapolar fungus. The conditions required for the completion of its life cycle in the laboratory have been determined. It is the only Clitocybe species from which the illudin group of sesquiterpenes has been isolated. Further, it produces compounds of the pulvinic acid group, a type of compound found in species of Xerocomus, Suillus, Paxillus, Gomphidius, Hydnum, and Hydnellum, but not in other Clitocybe species (except in Clitocybe subilludens with which it may be conspecific). Its chemical as well as it morphological distinctiveness support its exclusion from the genus Clitocybe. In the course of an investigation of single-basidiospore cultures of Clitocybe illudens (Schw.) Sacc. a number of biological and chemical properties of the fungus were examined: cultural characteristics, matingtype reactions, fruiting in the laboratory, and production of unusual metabolites. Single-basidiospore cultures (9-30 per sporophore) of C. illudens were isolated from each of 10 sporophores collected from 1965 to 1969, in seven localities in New York and New Jersey. The basidiospores were germinated at 25 C on 2% malt extract agar in Petri dishes. Germination after 10 da was close to 100%. A culture was obtained, with the aid of a dissecting microscope, by cutting out a block of agar containing a single, germinating basidiospore. Subsequently, it was found necessary to purify further the resulting cultures, either by isolating a single, germinating oidium of each, or a single hyphal tip. To determine the mating types of the cultures, these were combined in pairs within each strain, on the same medium at 25 C. Combinations made by placing inocula 3 cm apart on the medium in the center of a Petri dish did not readily form heterokaryons. Therefore, combinations were made on sterile, dry, paper discs (the type used to assay for penicillin). The disc was placed on the medium in the center of a Petri dish. Mycelial suspensions of each culture were prepared by lifting off the aerial mycelium of a culture with a sterile metal spatula, and crushing this on the inside of a test tube in 10 ml of sterile distilled water. One