I have chosen ethnogamy as one of the dependent variables because the choice of a marriage mate is one of the measures of cultural perseverance:

I tried to be a friend to Jane but we never really made friends. She was never a friend to me.

Alternative form: east-northeastward

Finally, although both the South and North Midlands are not known for their tropical climate, that's where mangoes grow. These aren't the tropical fruit, though, but what are elsewhere called green peppers.