Hi all. Definitely not a Peace Lily; I've grown a few of those over the years so am quite familiar with them. The leaves on this plant are longer and narrower; they also are of more substance than the leaves of Spathyphyllum. The flowers were small and white , closely spaced on a long stock and very strongly fragrant; nothing at all like the Spathyphyllum.
Thanks for all your ideas on my mystery plant. Normally, I'm well aware of all my plants but this came to me from a houseplant sale with no labelling.
