Each board may accept donations and aid from any person or corporation, and legacies and bequests by the last wills of deceased persons, for the aid or improvement of the parks and grounds under the control of the board. All money derived by any board from donations, legacies, and bequests shall, unless otherwise provided by the terms of the gift, legacy, or bequest, be deposited in the treasury of the city or city and county and withdrawn and paid out in the same manner as money legally appropriated for the support and improvement of the parks and grounds.