Belle de Boskoop

No, I really have no idea how to recognise the type of apple from just the blossoms.
But when the tree was just planted it had a lable attached disclosing the kind of apple. And Boskoop is so Dutch that I felt at home. (Boskoop is also a village in the Netherlands.)
Another name for Belle de Boskoop is Goudrenet, Goudreinet or Goudreinnette. My mother always used the Goudreinets for her "appeltaart", a delicious and typical Dutch apple pie. There are several recipes in the internet, this is just one of many (but comes close to what my mother made).