lower vascular plants having dichotomously branched sporophyte divided into aerial shoot and rhizome and lacking true roots

Psilotales is an order (i.e., order) of the Class Psilotopsida. This order contains one family, Psilotaceae, with only two living genera, Psilotum, small shrubby plants of the dry tropics commonly known as "Whisk ferns", and Tmesipteris, an epiphyte found in Australia, New Zealand, and New Caledonia. There has long been controversy about the relationships of the Psilotophyta, with some claiming that they are ferns (Pteridophyta), and others maintaining that they are descendants of the first vascular plants (the Psilophyta of the Devonian period).