Beacon St. north side, just west of Washington St.

From the 1887 photo series taken just before the widening of Beacon St., most likely by Augustine H. Folsom, a Boston photographer. This photo contains the mystery man, here leaning against the tree, who was posed in a number of the 1887 photos.
incl. Streets

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