It forms club-shaped basidia with four apical sterigmata on which oval, hyaline basidiospores are borne. Some basidiospores germinate repetitively by forming small spores instead of hyphae. The basidiospores are ballistically discharged and start new haploid mycelia called monokaryons. The hyphae of two compatible basidiospores then fuse to establish a dikarytic stage. Occasionally, sexual spores (basidiospores) are produced on infected plants. The basidiospores are ellipsoid and ornamented with amyloid warts. Omphalina is a genus of small agarics with white, nonamyloid, basidiospores and decurrent gills. Relatively few boletes have an apical pore at the distal end of their basidiospores. These fruiting bodies produce basidiospores which will spread the infection to other vulnerable trees. The species is a polypore, with pores on the underside that bear basidiospores. The basidiospores then infect the host plant. This basidiocarp produces basidiospores that will further infect new hosts. The puffball fungus "Calvatia gigantea" has been calculated to produce about five trillion basidiospores. The basidiospores disperse and start the infection process on host 1 again. Some basidiomycetes lack forcible discharge, although they still form basidiospores.