SUMMARY
The basidiomycete Sistotrema brinkmanni (Bres.) J. Erikss., as a nomenclatural entity, is a composite of homothallic, bipolar, and tetrapolar subspecies—all previously subjected to extensive cultural analysis by Biggs. Six further contributions to this system are discussed:
(1) | The marked enhancement of sporulation for the heterothallic as well as the homothallic subspecies on minimal media, | ||||
(2) | The detection of sporulation upon homokaryotic mycelia of heterothallic strains, an irregular feature recognized by Biggs in the bipolar Phlebia (Peniophora) ludoviciana (Burt) and by Raper and Krongelb in the tetrapolar Schizophyllum commune Fr., | ||||
(3) | The confirmation of homokaryotic dikaryosis as well as meiosis in homothallic strains of Sistotrema by the use of killing-kinetics and an analysis for recombination between auxotrophic mutations, | ||||
(4) | The demonstration, through nutritionally forced heterokaryosis and genetic recombination, that isolation between homothallic and bipolar counterparts of this system is not absolute, | ||||
(5) | The recognition of heterogenic incompatibility (recognized earlier by Biggs among “subgroups” of the tetrapolar subspecies) as common in all three subspecies, and | ||||
(6) | The induction of mutations (modifiers) that lead to self-sterility in homothallic strains and often disrupt homodikaryosis. |