Abstract: Cacti operads are a family of topological operads with many varieties, with connections to the little discs operads, fat graphs, metric Sullivan diagrams, and cobordism categories. Normalized cacti have a composition that corresponds to gluing genus 0 surfaces along their boundaries, but this composition is only associative up to homotopy. In this talk, I will introduce a new topological operad of bracketed trees, and use this to show that normalized cacti form an infinity operad (as a dendroidal space satisfying a weak Segal condition). This provides a blueprint for constructing infinity operads, with explicit coherence data, that do not arise from a nerve construction on a known operad. This is joint work with A. Linton, L. Bonatto, N. Wahl, M. Robertson, and S. Raynor, from the WIT III Workshop.