Page "Basidium" Paragraph 7

Some basidiomycetes lack forcible discharge, although they still form basidiospores.

In each of these groups, spore dispersal occurs through other discharge mechanisms.

For example, members of the order Phallales ( stinkhorns ) rely on insect vectors for dispersal ; the dry spores of the Lycoperdales ( puffballs ) and Sclerodermataceae ( earth balls and kin ) are dispersed when the basidiocarps are disturbed ; and species of the Nidulariales ( bird's nest fungi ) use a splash cup mechanism.

In these cases the basidiospore typically lacks a hilar appendage, and no forcible discharge occurs.

Each example is thought to represent an independent evolutionary loss of the forcible discharge mechanism ancestral to all basidiomycetes.