It may or may not have seeds but this is where they would be. You can let it dry to see if it produces anything. Unless you want seeds I would just trim it off when it becomes unsightly. It multiplies so easily I don't think it's worth the effort.
In the Spathiphyllum the white part is the spathe.The central part is the spadix. The spadix contains the tiny flowers on the outside and the seeds inside. The spadix will turn brown then black when the seeds are set. Slice open the spadix to scrape out the seeds. Because of hybridization the seeds may not be viable.
