See marriage record for son Louis Gardner Teele - this gives Emma’s surname as “Dean”. Also 1900 census (see notes with spouse) says Emma’s parents were born in Scotland.

1870 CENSUS, WALTHAM, MIDDLESEX, MA:
This has to be the right family. Robert Dean, age 25, born in Scotland, is head of houehold. Wife is Jane Dean, age 21, also born in Scotland. Children are Mary, age 4, and Emma, age 2.

1900 CENSUS, WALTHAM WARD 3, MIDDLESEX, MA:
Robert Dean, age 54, born in Scotland, immigration 1860, widowed. Living with daughter Hellen, born Mar 1883. Both of Hellen’s parents born in Scotland.