The problem with FamilySearch is that they use the patronymic as a last name. So whoever transcribed Greta's birth information saw that her father was Johan Clem(ets)s(on) and considered that her last name. So in reality she was Greta Johansdotter Tulisalo (the name of the farm). You can see the entire family in the communion book:
http://www.sukuhistoria.fi/sshy/kirjat/Kirkonkirjat/isokyro/...The original birth information can be found on the national archives website:
http://digi.narc.fi/digi/view.ka?kuid=6655879I really wish that FamilySearch had included the farm names when they had these transcribed, cause if you just look at their information it's impossible to find the family in the communion book. And there might be several couples with the same name, so getting families mixed up is extremely easy when using FamilySearch.