Md. Code, Tax - Property § 12–104

(a) Except as provided in subsection (b) of this section, the consideration payable, including the amount of any mortgage or deed of trust assumed by the grantee, or the principal amount of the secured debt incurred, shall be described in:

(1) the recitals or the acknowledgment of the instrument of writing; or

(2) an affidavit under oath that accompanies the instrument of writing and that is signed by a party to the instrument of writing or by an agent of a party.

(b) Security agreements filed in accordance with § 9-502 of the Maryland Uniform Commercial Code are governed by the requirements of that section and not by subsection (a) of this section.