Roots of the bracken fern (Pteridium aquilium) isolated from a sexual sporeling have been successfully cultured in vitro. Initial studies were directed toward a definition of growth conditions and media. The roots are now cultured in a very simple medium consisting of a Knudson mineral salt solution with added minor elements and 1.5% sucrose, at an initial pH of 5.5. A striking response leading eventually to the formation of laterals was observed when indoleacetic acid was added to the medium. After prolonged culture, without transfer, some of the stock cultures on basal medium gave rise to gametophytes through the process of apospory.