The scientific name for the peace lily is Spathiphyllum. I bought mine in the beginning of November 2015 in a store for only E3.50 and it was already this big. But unfortunatelly I don't know if its the Spathiphyllum Verdi, the Spathiphyllum Sweet Romano or the Spathiphyllum Lauretta.
But I do know it was like 75 cm in lenght when I bought it.
When I bought it, it had 1 flower but I had to cut it off because it turned green. However I placed it temporary in the glass with my avocado seed
It's a cheap plant to buy, simple to care for with easy to follow care instructions and will also help filter the surrounding air of various toxins. When it comes to the meaning of the Peace Lily name this is down to the flowers with the white raised spathe looking like a white flag of surrender.
I hope it grows much much bigger but because I don't know which version I have I dont know how big its going to get eventually.
I also have a very little version of the peace lily in my bedroom, its called the Spathiphyllum Chopin. That one is like 25 cm and will say that way. Because I wanted a bigger version I bought this bigger one for in my living room.
Update on Februari 20th: I have 5 flowers coming up from this plant. When I bought it it only had 1 flower and I had to cut it after it got 'old'.