Md. Code, Estates and Trusts § 4–401

A legatee, other than the testator’s spouse, who fails to survive the testator by 30 full days is considered to have predeceased the testator, unless the will of the testator:

(1) Expressly creates a presumption that the legatee is considered to survive the testator; or

(2) Requires that the legatee survives the testator for a stated period in order to take under the will and the legatee survives for the stated period.