More than 50 years removed from high school, Marlo Sedki still remembers C.B. Branham well. “We thought she was pretty strict at the time, but she was wonderful,” Sedki said of the legendary dean of Brenau Academy, which operated as an all-girls boarding school from 1928 to 2011. On Saturday, during Brenau University’s alumnae reunion weekend and “May Day” celebration, Sedki and other academy graduates plan to gather for the dedication of a marker and garden at the school off Boulevard and Academy Street.