SPORE DISCHARGE IN BASIDIOMYCETES: A UNIFIED THEORY.

Olive's demonstration that a bubble bursting at the basidiospore apiculus breaks the connection between spore and sterigma convincingly explains the mechanism of severance; but it does not explain spore discharge, because the bursting force is not applied in the appropriate direction. The form of the developing spore and sterigma shows that the spore is forcibly abstricted while the membrane is still fluid. If the abstricting force persists until the fracture of the sterigma, it provides a mechanism whereby the spore is reliably discharged.