When was "Mary D. Mortenson" born? Did she emigrate from Sweden? (What is the Whiteside in parentheses after her name? Is it a married name? Is it a location?) Was Elna born in Sweden? When? Where did this family live after emigrating, if they emigrated?
There won't be a "Mortenson" family. (The Swedish spelling would be Mårtensson or -- for females -- Mårtensdotter.) Mårtensson is not a surname which passed down from generation to generation, or at least it wasn't back in the 1800s and earlier. It was a patronymic last name which changed each generation depending upon the given name of the father. The father was (depending on the time period, of course) Mårten Xsson (where X would be the given name of his father. Mårten's children would have the patronymic last name of Mårtensson (literally, Mårten's son) or Mårtensdotter (literally, Mårtensdotter).
Mary would have been called Maria (or Maja, a form of Maria) in Sweden. I'm not really sure what her last name was in Sweden. Was it Mårtensson/Mårtensdotter or was it some form of Whiteside? (Whiteside is not a Swedish name.)
To look for a Maria (or Maja) D. with no certain last name who lived "around" Malmö (a city with many parishes and "around" makes it sound as if she probably lived in some parish in the county of Malmöhus and not in the city itself) is an impossible task without more information. At the very least, do you have her full birthdate? (day/month/year) Do you know when she left Sweden? Can you confirm her maiden name? Can you tell where she lived (specifically; a city or town, not just a country, state, or region) after emigrating?
This tells the sort of information usually needed to have a chance of finding people in Swedish records.