Section 80. For the purpose of carrying out section thirty-five, the commissioner may take or acquire, in fee or otherwise, on behalf of the commonwealth, by purchase, gift, devise, or eminent domain under chapter seventy-nine, any land or easements or interests in land within the metropolitan parks district, although the land so taken, or any part thereof, be already a public way; provided, that the concurrence of the city council in Boston for Suffolk county or the concurrence of each other county or city or town outside of Suffolk county, wherein any portion of any public way, land or rights in land is taken by eminent domain, be obtained to the taking of said portion by vote of its county commissioners, city council or selectmen, respectively.