Listed as Mrs. May B. Thearle, source: Cookie Grama Ethel & Ancestral Lines of Chester Everts Howell. California Birth Index shows son, Bruce and his mother's name as Sexton.
Thearle May Sexton Birth Date & Married Names (Some records appeared as though Thearle was her surname. It is unclear why her union with Mr. Brenna does not show...possibly because they didn't marry.)