2. Pteridium Gled. ex Scop. (bracken)
One species, nearly worldwide.
Although traditionally thought to comprise a single species consisting of a
dozen varieties grouped into two subspecies, several recent authors have
recognized two to several species. The interrelationships among the various
taxa require further study before the question of species limits in Pteridium
can be resolved. Until these can be elucidated, the two taxa present in
Missouri are retained as varieties of P. aquilinum.