Every county, municipality, and other political subdivision of this state is empowered to expend money from available sources to aid in the purchase of areas within the county, municipality or political subdivision for park purposes within the meaning of this part, the park to become the property of the state, to be improved, cared for and administered by the department of environment and conservation as a part of the state park system hereinabove mentioned; provided, that the governor and commissioner of environment and conservation shall have first agreed in writing to accept the same.