Nuclear Behavior in the Basidium of Fomes Annosus

Meiotic division in Fomes annosus is similar to that reported for other higher fungi. Nuclei in dikaryotic cells prior to fusion in the basidia are long, thin, and double‐stranded with paired heterochromatic areas. Various stages of prophase are similar to those in higher plants. At metaphase I and II seven pairs of chromosomes are aligned in a circle and the chromatids migrate to opposite poles established by two centrioles. The centrioles function in the movement of the nuclei in the basidium, nuclear alignment prior to fusion, establishment of poles for division, and the migration of the nuclei into the basidiospore. After nuclei migrate into the basidiospore, they soon divide, producing a binucleate spore.