psilophyte
noun
psi·lo·phyte ˈsī-lə-ˌfīt 
: any of a division (Psilophyta) of simple dichotomously branched plants that first appeared during the Late Silurian, are now limited to two extant genera, lack true leaves and roots, and include the oldest known land plants with vascular tissue
psilophytic
ˌsī-lə-ˈfi-tik
adjective 
Word History
Etymology
New Latin Psilophyton, genus of plants, from Greek psilos bare, mere (probably akin to Greek psēn to rub) + phyton plant — more at phyto-
First Known Use
1933, in the meaning defined above