Another tree has a Jannis "John" Wemelsfelder born 27 Apr 1825 at Groede married to a Maria Baptiste Triestram born 15 Feb 1826 at Nieuwvliet. Those dates don't exactly match the ones in the 1880 census but that isn't the first time that this happened.

We do have in Genlias:

Source Civil register - Marriage
Archive location Zeeuws Archief
General Number of finding aid: 25.40
Municipality: Groede
Type of record: Huwelijksakte
Record number: 13
Registration date: 11-08-1852
Groom Jannis Wemelsfelder
Age: 27
Place of birth: Groede
Bride Maria Tristram
Age: 26
Place of birth: Nieuwvliet
Father groom Jacob Wemelsfelder
Mother groom Maria Cornelis
Father bride Joannis Tristram
Mother bride Anthonietta Maria de Maillie