When sperms of Funaria and Pteris are put together near the archegonia of Pteris only sperms of Pteris readily enter the archegonia and reach the egg. The reason for this is
archegonia of Pteris secrete a substance which attracts sperms of Pteris
archegonia of Pteris secrete a substance which repels sperms of Pteris
sperms of Funaria are less mobile
sperms of Funaria are killed when mixed with sperms of Pteris