This is most likely George Peabody Gardner, Jr.; Rose Phinney Grosvenor Gardner, his wife; and their six children - Catherine P Gardner (15), Isabella S Gardner (13), George P Gardner (11), John L Gardner (5), Rose P Gardner (4), Robert G Gardner (3)

[Courtesy of the Digital Commonwealth (CC BY-NC-ND). From the Brookline Photograph Collection published by the Public Library of Brookline]