Every cemetery authority which now or hereafter maintains a cemetery may place its cemetery under endowment care and establish, maintain, and operate an endowment care fund. Endowment care and special care funds consisting of trust funds created by irrevocable trust agreements may be commingled for investment and the income therefrom shall be divided between the endowment care and special care funds in the proportion that each fund contributed to the principal sum invested. Special care funds derived from trusts created by a revocable agreement shall not be commingled for investment and shall be accounted for separately from all other funds. The funds may be held in the name of the cemetery authority or its directors or in the name of the trustees appointed by the cemetery authority.