Psilophytales means naked plants . They are oldest and simplest vascular plants . All the members are fossils . They belong to Devonian period .
Rhynia
Rhynia were discovered by Kidston and Lang in Rhynie locality of Aberdeenshire in Scotland . The name Rhynia has been derived from its locality Rhynie . They are found in perfect petrified state . They grow near volcanoes in habitats saturated with acid water from hot springs . They had subterranean , dichotomously branched rhizome and rootless , leafless shoot . Rhizome bears rhizoids in tuft .
Rhynia major was long and sporophytic phase . Rhynia gwynne-vaughani was short and gametophytic phase . Shoot had protostele . The shoot had adventitious branches ( for vegetative propagation ) and hemispherical projections ( stomata / archegonia , according to Pant ). Sporangium were borne singly or in groups on apices ( difference with psilotales ) . Spores had typical tri-radiate markings .
Horneophyton ( rootless , leafless ) and asteroxylon ( rootless but with leaves ) were also found along with rhynia at Rhynie in Scotland .