Per stirpes rule of descent.

Iowa Code § 633A.1103, under IOWA TRUST CODE.

Iowa Code § 633A.1103

Unless the trust instrument provides otherwise, all gifts to multigeneration classes shall be per stirpes. 99 Acts, ch 125, §3, 109 C2001, §633.1103 2005 Acts, ch 38, §54 CS2005, §633A.1103