Abstract
In this paper the widely held opinion that the PIE collectives were a derivational category of neuter gender is contested. It is shown that the later agreement patterns of the feminine gender and the neuter plural are better derived from an inflectional category “collective” already marked by agreement. Next, the implications of this reconstruction for the categorial system of the PIE noun are explored and it is proposed that the late PIE gender/number system results from the reduction of an earlier noun class system with many classes, marked by agreement. Finally, the reconstruction of the early PIE state of affairs is illustrated with a typological parallel from Amazonia.