Psilotum (whisk fern) is a genus of fern-like vascular plants, one of two genera in the family Psilotaceae, order Psilotales, and class Psilotopsida (the other being Tmesipteris). The name of the genus is from Greek psilos = naked, because it lacks organs, such as leaves, normally found in other ferns.
Read more about Psilotum: Species and Distribution, Relation To Ferns, Gametophyte