Technical Abstract: Oxycaryum cubense (Poepp. & Kunth) Palla, Cuban club-rush, is an invasive aquatic weed that is spreading northward in the southeastern United States. It is reported for the first time from Mississippi and from significantly farther northward in Alabama than previously known. Oxycaryum cubense dissemination and rapid population growth are attributed to two types of reproduction, corky floating achenes and asexual reproduction by fragmentation. An illustration of O. cubense and photos of its habit and habitat are provided.