No person who has been a member of the park and recreation board within six months from the time of making of the sale or purchase shall be directly or indirectly pecuniarily interested in the sale to or purchase from such municipality by or through the agency or instance of such board of any land or interest in land, and any sale to or by such municipality made in violation of this provision, shall, at the instance of such municipality, be held to be against public policy and void and may be rescinded by such municipality. If any member of the board is a stockholder in a corporation owning land or interest in land desired by such municipality for park and recreation purposes, or is the owner of an individual interest in the land desired for such purposes, or if any member of the board is a stockholder in a corporation desiring to purchase land proposed to be sold by such municipality at the instance of the board, such member may in open meeting of the board disclose his interest, which shall appear on the minutes of the meeting, and retire from the meeting of the board, and the other members of the board, if a quorum remains, may consider the matter and decide it as they deem best; and any such sale shall be legal and valid. If any member of the board is the owner of the land which it is desired to acquire for such municipality for any such purpose, the land, if acquired, shall be acquired by the exercise of the right of eminent domain, and the petition or proceeding for condemnation shall set forth the facts in regard to the ownership by a member of the board.